Considerations for Pharmacoepidemiological Studies of Drug-Cancer Associations

Immunosuppression and cancer risk in kidney transplant recipients: A retrospective cohort study

We assessed whether contemporary immunosuppression agents were associated with cancer among kidney transplant recipients (KTR), and if this association varied by age and sex. We studied a retrospective province-wide cohort of primary KTR (1997-2016). Employing multivariable Cox models, we estimated associations of cumulative doses of prednisone, mycophenolate and tacrolimus administered over the past 10 years, lagged by 2 years, with the incidence of primary malignant neoplasms (PMN). We assessed interactions with age and sex. To assess the impact of exposure recency, we used weighted cumulative exposure (WCE) modeling. Among 1064 KTR, 108 (10.2%) developed PMN over median follow-up of 73 months (interquartile range: 32-120). Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) of 0.96 (0.64-1.43), 1.34 (0.96-1.86), and 1.06 (0.88-1.29) were estimated for cumulative daily doses of prednisone (5 mg), mycophenolate (1000 mg), and tacrolimus (2 mg) administered continuously over the past 10 years, respectively. PMN risk associated with cumulative tacrolimus exposure was modified by age (interaction p = .035) and was more pronounced in 15-year and 30-year-old KTR (aHRs of 1.57 [1.08-2.28] and 1.31 [1.03-1.66], respectively) in comparison to older KTR. PMN risk increase associated with higher cumulative mycophenolate dose was more pronounced in females (aHR = 1.86 [1.15-3.00]) than in males (aHR = 1.16 [0.74-1.81]; interaction p = .131). WCE analyses suggested increased PMN risk the higher the mycophenolate doses taken 5-10 years ago. A trend toward increased PMN risk with long-term mycophenolate exposure, particularly in females, and more pronounced risk with long-term tacrolimus exposure in younger KTR, identify opportunities for tailored immunosuppression to mitigate cancer risk.

SGLT-2 Inhibitor Use and Cause-Specific Hospitalization Rates: An Outcome-Wide Study to Identify Novel Associations of SGLT-2 Inhibitors

Sodium-glucose co-transporter 2 inhibitors (SGLT2is) have demonstrated multifaceted pharmacological effects. In addition to type 2 diabetes, they are now indicated for heart failure and chronic kidney disease. This study aimed to identify novel associations between SGLT2i use and health outcomes using real-world data. Using linked data from a nationwide diabetes registry in Australia, we compared hospitalization rates in people living with type 2 diabetes commencing treatment with SGLT2i and dipeptidyl peptidase-4 inhibitor (DPP4i) between December 1, 2013, and June 30, 2019. Cause-specific hospitalizations were categorized across three hierarchies of diagnoses (first, first three, and first four digits of International Classification of Diseases, Tenth Version, Australian Modification codes). Incidence rate ratio (IRR) and 95% confidence interval (95% CI) for each cause-specific hospitalization were estimated using negative binomial regression. In the first hierarchy, hospitalization rates were lower across most diagnosis groups among SGLT2i initiators (n = 99,569) compared with DPP4i initiators (n = 186,353). In the second and third hierarchies, there were lower hospitalization rates relating to infections, anemias, and obstructive airway diseases among SGLT2i initiators compared with DPP4i initiators. These included sepsis (IRR: 0.60, 95% CI: 0.51-0.72) anemia (IRR: 0.55, 95% CI: 0.46-0.66), and chronic obstructive pulmonary diseases (IRR: 0.52, 95% CI: 0.40-0.68), as well as for previously known associations (e.g., heart failure (IRR: 0.63, 95% CI: 0.56-0.70)). SGLT2is have previously uncharacterized associations on a range of important clinical outcomes; validation of these associations requires further study, some of which may suggest novel benefits or new indications for SGLT2is.

Antipsychotic Use and Risk of Breast Cancer in Women With Severe Mental Illness: Replication of a Nationwide Nested Case-Control Database Study

BACKGROUND AND HYPOTHESIS

Breast cancer is more prevalent in women with severe mental illness than in the general population, and use of prolactin-increasing antipsychotics may be a contributing factor.

STUDY DESIGN

A nested case-control study was conducted using the Swedish nationwide registers (inpatient/outpatient care, sickness absence, disability pension, prescribed drugs, cancers). All women aged 18-85 years with schizophrenia/schizoaffective/other nonaffective psychotic disorder/bipolar disorder and breast cancer (cases) were matched for age, primary psychiatric diagnosis, and disease duration with five women without cancer (controls). The association between cumulative exposure to prolactin-increasing/prolactin-sparing antipsychotics and breast cancer was analyzed using conditional logistic regression, adjusted for comorbidities and co-medications.

STUDY RESULTS

Among 132 061 women, 1642 (1.24%) developed breast cancer between 2010 and 2021, at a mean age of 63.3 ± 11.8 years. Compared with 8173 matched controls, the odds of breast cancer increased in women with prior exposure to prolactin-increasing antipsychotics for 1-4 years (adjusted odds ratio [aOR] = 1.20, 95% confidence interval [CI] = 1.03-1.41), and for ≥ 5 years (aOR = 1.47, 95%CI = 1.26-1.71). There were no increased or decreased odds of breast cancer with exposure to prolactin-sparing antipsychotics of either 1-4 years (aOR = 1.17, 95%CI = 0.98-1.40) or ≥5 years (aOR = 0.99, 95%CI = 0.78-1.26). The results were consistent across all sensitivity analyses (ie, according to different age groups, cancer types, and primary psychiatric diagnosis).

CONCLUSIONS

Although causality remains uncertain, exposure to prolactin-elevating antipsychotics for ≥ 1 year was associated with increased odds of breast cancer in women with severe mental illness. When prescribing antipsychotics, a shared decision-making process should consider individual risk factors for breast cancer.

Low-Dose Aspirin and Prevention of Colorectal Cancer: Evidence From a Nationwide Registry-Based Cohort in Norway

INTRODUCTION

To examine the association between low-dose aspirin use and risk of colorectal cancer (CRC).

METHODS

In this nationwide cohort study, we identified individuals aged 50 years or older residing for 6 months or more in Norway in 2004-2018 and obtained data from national registers on drug prescriptions, cancer occurrence, and sociodemographic factors. Multivariable Cox regression models were used to estimate the association between low-dose aspirin use and CRC risk. In addition, we calculated the number of CRC potentially averted by low-dose aspirin use.

RESULTS

We included 2,186,390 individuals. During the median follow-up of 10.9 years, 579,196 (26.5%) used low-dose aspirin, and 38,577 (1.8%) were diagnosed with CRC. Current use of aspirin vs never use was associated with lower CRC risk (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.84-0.90). The association was more pronounced for metastatic CRC (HR 0.79; 95% CI 0.74-0.84) than regionally advanced (HR 0.89; 95% CI 0.85-0.92) and localized CRC (HR 0.93; 95% CI 0.87-1.00; P heterogeneity = 0.001). A significant trend was found between duration of current use and CRC risk: HR 0.91 (95% CI 0.86-0.95) for <3 years, HR 0.85 (0.80-0.91) for ≥3 and <5 years, and HR 0.84 (0.80-0.88) for ≥5 years of use vs never use ( P trend < 0.001). For past use, HR were 0.89 (95% CI 0.84-0.94) for <3 years, 0.90 (0.83-0.99) for ≥3 and <5 years, and 0.98 (0.91-1.06) for ≥5 years since last use vs never use ( P -trend < 0.001). We estimated that aspirin use averted 1,073 cases of CRC (95% CI 818-1,338) in the study period.

DISCUSSION

In this nationwide cohort, use of low-dose aspirin was associated with a lower risk of CRC.

Effect of statin treatment on the risk of cancer in patients with heart failure: A target trial emulation study

PURPOSE

A recent observational study suggested statins could reduce cancer diagnosis in patients with heart failure (HF). The findings need to be validated using robust epidemiological methods. This study aimed to evaluate the effect of statin treatment on the risk of cancer in patients with HF.

METHODS

We conducted two target trial emulations using primary care data from IQVIA Medical Research Database-UK (2000 to 2019) with a clone-censor-weight design. The first emulated trial addressed the treatment initiation effect: initiating within 1 year versus not initiating a statin after the HF diagnosis. The second emulated trial addressed the cumulative exposure effect: continuing a statin for ≤3 years, 3-6 years, and >6 years after initiation. The study outcomes were any incident cancer and site-specific cancer diagnoses. Weighted pooled logistic regression models were used to estimate 10-year risk ratios (RR). 95% confidence intervals (CIs) were estimated using non-parametric bootstrapping.

RESULTS

The first emulated trial showed that, compared to no statin, statins did not reduce the cancer risk in patients with HF (RR, 1.05; 95% CI, 0.94-1.15). The second emulated trial showed that, compared to treatment ≤3 years, statins with longer durations did not reduce the cancer risk (3-6 years: RR, 0.94; 95% CI, 0.70-1.33. >6 years: RR, 0.97; 95% CI, 0.79-1.26). No significant risk difference was observed on any site-specific cancer diagnoses.

CONCLUSIONS

The results from the target trial emulations suggest that statin treatment is not associated with cancer risk in patients with HF.

Cardiovascular and mortality outcomes with GLP-1 receptor agonists vs other glucose-lowering drugs in individuals with NAFLD and type 2 diabetes: a large population-based matched cohort study

AIMS/HYPOTHESIS

We aimed to determine whether the use of glucagon-like peptide-1 receptor agonists (GLP-1RA) in individuals with non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus decreases the risk of new-onset adverse cardiovascular events (CVEs) and mortality rate compared with other glucose-lowering drugs in a real setting at a population level.

METHODS

We conducted a population-based propensity-matched retrospective cohort study using TriNetX. The cohort comprised patients over 20 years old who were newly treated with glucose-lowering drugs between 1 January 2013 and 31 December 2021, and followed until 30 September 2022. New users of GLP-1RAs were matched based on age, demographics, comorbidities and medication use by using 1:1 propensity matching with other glucose-lowering drugs. The primary outcome was the new onset of adverse CVEs, including heart failure, composite incidence of major adverse cardiovascular events (MACE; defined as unstable angina, myocardial infarction, or coronary artery procedures or surgeries) and composite cerebrovascular events (defined as the first occurrence of stroke, transient ischaemic attack, cerebral infarction, carotid intervention or surgery), and the secondary outcome was all-cause mortality. Cox proportional hazards models were used to estimate HRs.

RESULTS

The study involved 2,835,398 patients with both NAFLD and type 2 diabetes. When compared with the sodium-glucose cotransporter 2 (SGLT2) inhibitors group, the GLP-1RAs group showed no evidence of a difference in terms of new-onset heart failure (HR 0.97; 95% CI 0.93, 1.01), MACE (HR 0.95; 95% CI 0.90, 1.01) and cerebrovascular events (HR 0.99; 95% CI 0.94, 1.03). Furthermore, the two groups had no evidence of a difference in mortality rate (HR 1.06; 95% CI 0.97, 1.15). Similar results were observed across sensitivity analyses. Compared with other second- or third-line glucose-lowering medications, the GLP-1RAs demonstrated a lower rate of adverse CVEs, including heart failure (HR 0.88; 95% CI 0.85, 0.92), MACE (HR 0.89; 95% CI 0.85, 0.94), cerebrovascular events (HR 0.93; 95% CI 0.89, 0.96) and all-cause mortality rate (HR 0.70; 95% CI 0.66, 0.75).

CONCLUSIONS/INTERPRETATION

In individuals with NAFLD and type 2 diabetes, GLP-1RAs are associated with lower incidences of adverse CVEs and all-cause mortality compared with metformin or other second- and third-line glucose-lowering medications. However, there was no significant difference in adverse CVEs or all-cause mortality when compared with those taking SGLT2 inhibitors.

Phosphodiesterase Type 5 Inhibitors in Men With Erectile Dysfunction and the Risk of Alzheimer Disease: A Cohort Study

BACKGROUND AND OBJECTIVES

Repurposing phosphodiesterase type 5 inhibitors (PDE5Is) as drugs for Alzheimer disease (AD) risk reduction has shown promise based on animal studies. However, evidence in humans remains inconclusive. Therefore, we conducted a cohort study to evaluate the association between PDE5I initiation compared with nonuse and the risk of developing AD in men with erectile dysfunction (ED).

METHODS

Using electronic health records from IQVIA Medical Research Data UK (formerly known as the THIN database), we identified men aged ≥40 years with a new diagnosis of ED between 2000 and 2017. Individuals with a previous diagnosis of dementia, cognitive impairment, confusion, or prescription for dementia symptoms were excluded. The occurrence of incident AD was identified using diagnostic read codes. To minimize immortal-time bias, PDE5I initiation was treated as a time-varying exposure variable. Potential confounders were adjusted using inverse probability of treatment weighting based on propensity scores. Cox proportional hazard models were used to estimate the adjusted hazard ratio (HR) with 95% CIs. A secondary analysis explored the association between AD and the cumulative number of PDE5I prescriptions. Sensitivity analyses included lag (delay) periods of 1 and 3 years after cohort entry to address the prodromal stage of AD.

RESULTS

The study included 269,725 men, with 1,119 newly diagnosed with AD during a median follow-up of 5.1 (interquartile range 2.9-8.9) years. The adjusted HR in PDE5I initiators compared with nonuse was 0.82 (95% CI 0.72-0.93). The associated risk of AD decreased in individuals issued >20 prescriptions: HR 0.56 (95% CI 0.43-0.73) for 21-50 prescriptions and HR 0.65 (95% CI 0.49-0.87) for >50 prescriptions. Sensitivity analysis with a 1-year lag period supported the primary findings (HR 0.82, 95% CI 0.72-0.94), but the results differed with the inclusion of a 3-year lag period (HR 0.93, 95% CI 0.80-1.08).

DISCUSSION

PDE5I initiation in men with ED was associated with a lower risk of AD, particularly in those most frequently issued prescriptions. The differences between primary and sensitivity analyses highlight the need to explore the optimal lag period. To enhance the generalizability of our findings, a randomized controlled trial including both sexes and exploring various PDE5I doses would be beneficial to confirm the association between PDE5I and AD.

Risk of thyroid cancer associated with glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors in patients with type 2 diabetes: A population-based cohort study

AIMS

To determine the potential association between the use of either glucagon-like peptide-1 receptor agonists (GLP-1RAs) or dipeptidyl peptidase-4 (DPP-4) inhibitors, and the risk of thyroid cancer in individuals with type 2 diabetes.

MATERIALS AND METHODS

This population-based cohort study used claims data from the Korean National Health Insurance Database, 2014-2020. Two distinct cohorts were established to compare each incretin-based drug with sodium-glucose cotransporter-2 (SGLT2) inhibitors, chosen as active comparators because of their previous non-association with thyroid cancer, and their common usage as add-on therapy to metformin along with GLP-1RAs and DPP-4 inhibitors. The first cohort included 21 722 new users of GLP-1RAs and 326 993 new users of SGLT2 inhibitors, whereas the second cohort included 904 300 DPP-4 inhibitor new users and 112 017 SGLT2 inhibitor new users. The outcome was the time to incident thyroid cancer. Weighted Cox proportional models were used to estimate hazard ratios of thyroid cancer incidence associated with incretin-based drugs of interest.

RESULTS

The use of GLP-1RAs was not associated with an increased risk of thyroid cancer (weighted hazard ratio 0.98, 95% confidence interval 0.62-1.53) compared with that of SGLT2 inhibitors. Using DPP-4 inhibitors was also not associated with an increased risk of thyroid cancer (0.95, 0.79-1.14) compared with that of SGLT2 inhibitors. No significant effect modifications were observed across subgroup analyses. Sensitivity analyses, including alternative outcome definition analysis of medullary thyroid cancer, were consistent with the primary analysis results.

CONCLUSIONS

GLP-1RAs and DPP-4 inhibitors were not associated with an increased risk of thyroid cancer in individuals with type 2 diabetes.

Risk of cancer with immunosuppressants compared to immunomodulators in multiple sclerosis: A nested case-control study within the French nationwide claims database

PURPOSE

The objective was to compare the risk of malignancies in real-world settings between exclusive immunosuppressant (IS) and immunomodulator (IM) use in multiple sclerosis (MS).

METHODS

A nested case-control study was designed within a new-user cohort of all patients with MS who initiated a first IM or IS between 2008 and 2014, and without cancer history, using the information of the SNDS nationwide French claims database. Incident cancer cases were matched with up to six controls on year of birth, sex, initiation date, and disease risk score of cancer. A conditional logistic regression (odds ratio [95% confidence interval]) was used to compare exclusive IS versus IM use during follow-up and according to three use durations.

RESULTS

From 28 720 newly treated patients with MS, 407 incident cancers were observed during the follow-up with 2324 matched controls. A significant increase in cancer risk was observed for IS compared with IM (1.36 [1.05, 1.77]), with similar increases for the first 2 years of use but not for ≥2 years (1.06 [0.65, 1.75]). Similar increase was also observed for IS with indications other than MS (1.37 [1.04, 1.81]) but not for IS indicated only in MS (1.03 [0.45, 2.34]).

CONCLUSIONS

Compared with IM, a 37% increase in cancer risk was observed for IS with indications other than MS and used for a short duration (≤2 years) but not for IS indicated only in MS. The absence of risk for prolonged exposure of IS with indications other than MS is not in favor of a causal relation with these drugs.

Importance of accounting for timing of time-varying exposures in association studies: Hydrochlorothiazide and non-melanoma skin cancer

PURPOSE

Hydrochlorothiazide (HCTZ), a widely prescribed antihypertensive drug with photosensitising properties, has been linked with non-melanoma skin cancer (NMSC) risk. However, previous analyses did not fully explore if and how the impact of past HCTZ exposures accumulates with prolonged use and/or depends on time elapsed since exposures. Therefore, we used different models to more comprehensively assess how NMSC risk vary with HCTZ exposure, and explore how the results may depend on modeling strategies.

METHODS

We used different parametric models with alternative time-varying exposure metrics, and the flexible weighted cumulative exposure model (WCE) to estimate associations between HCTZ exposures and NMSC risk in a population-based cohort of HCTZ users over 65 years old, in the province of Ontario, Canada.

RESULTS

Among 3844 HCTZ users, 273 developed NMSC during up to 8 years of follow-up. In parametric models, based on all exposures, increased duration of past HCTZ use was associated with an increase of NMSC risk but cumulative dose showed no systematic association. Yet, WCE results suggested that only exposures taken 2.5-4 years in the past were associated with the current NMSC hazard. This finding led us to re-define the parametric models, which also confirmed that any HCTZ dose taken outside this time-window were not systematically associated with NMSC incidence.

CONCLUSIONS

Our analyses illustrate how flexible modeling may yield new insights into complex temporal relationships between a time-varying drug exposure and risks of adverse events. Duration and recency of antihypertensive agents exposures must be taken into account in evaluating risk and benefits.

Published registry-based pharmacoepidemiologic associations show limited concordance with agnostic medication-wide analyses

OBJECTIVES

To assess how the results of published national registry-based pharmacoepidemiology studies (where select associations are of interest) compare with an agnostic medication-wide approach (where all possible drug associations are tested).

STUDY DESIGN AND SETTING

We systematically searched for publications that reported drug associations with any, breast, colon/colorectal, or prostate cancer in the Swedish Prescribed Drug Registry. Results were compared against a previously performed agnostic medication-wide study on the same registry.

PROTOCOL

https://osf.io/kqj8n.

RESULTS

Most published studies (25/32) investigated previously reported associations. 421/913 (46%) associations had statistically significant results. 134 of the 162 unique drug-cancer associations could be paired with 70 associations in the agnostic study (corresponding drug categories and cancer types). Published studies reported smaller effect sizes and absolute effect sizes than the agnostic study, and generally used more adjustments. Agnostic analyses were less likely to report statistically significant protective associations (based on a multiplicity-corrected threshold) than their paired associations in published studies (McNemar odds ratio 0.13, P = 0.0022). Among 162 published associations, 36 (22%) showed increased risk signal and 25 (15%) protective signal at P < 0.05, while for agnostic associations, 237 (11%) showed increased risk signal and 108 (5%) protective signal at a multiplicity-corrected threshold. Associations belonging to drug categories targeted by individual published studies vs. nontargeted had smaller average effect sizes; smaller P values; and more frequent risk signals.

CONCLUSION

Published pharmacoepidemiology studies using a national registry addressed mostly previously proposed associations, were mostly "negative", and showed only modest concordance with their respective agnostic analyses in the same registry.

Effects of ranitidine and nizatidine on the risk of gastrointestinal cancer

Purpose

Gastrointestinal (GI) cancer occurs in digestive organs such as the stomach, colon, liver, esophagus, and pancreas. About 83,034 cases occurred in Korea alone in 2020. Dietary factors, alcohol consumption, Helicobacter pylori (H. pylori), and lifestyle factors increase the incidence of diseases such as gastritis, peptic ulcer, pancreatitis, and gastroesophageal reflux disease (GERD), which can develop into GI cancer. However, in 2019, the US Food and Drug Administration announced that the drugs ranitidine and nizatidine, which are used for digestive disorders, contain carcinogens. In this study, we investigated the effects of ranitidine and nizatidine on the development of GI cancer.

Materials and methods

In this study, using National Health Insurance Service-National Sample Cohort (NHIS-NSC) version 2.5 (updated from 2002 to 2019), subjects who developed GI cancer were enrolled in the case group, and those who were at risk of, but did not develop, cancer were enrolled in the control group. Thereafter, risk-set matching was performed (1:3 ratio) by sex and age at the time of diagnosis of cancer in the case group. Through this procedure, 22,931 cases and 68,793 controls were identified. The associations of ranitidine and/or nizatidine with GI cancer were confirmed by adjusted odds ratios (aORs) and 95% confidence intervals (CIs) calculated through conditional logistic regression analysis.

Results

The aORs of ranitidine and/or nizatidine users were lower than those of nonusers in all average prescription days groups (< 30 days/year: aOR [95% CI] = 0.79 [0.75-0.82]; 30-59 days/year: aOR [95% CI] = 0.66 [0.59-0.73]; 60-89 days/year: aOR [95% CI] = 0.69 [0.59-0.81]; ≥ 90 days/year: aOR [95% CI] = 0.69 [0.59-0.79]). Sensitivity analyses were conducted with different lag periods for the onset of GI cancer after drug administration, and these analyses yielded consistent results. Additional analyses were also performed by dividing subjects into groups based on cancer types and CCI scores, and these analyses produced the same results.

Conclusion

Our study, using nationwide retrospective cohort data, did not find evidence suggesting that ranitidine and nizatidine increase the risk of GI cancer. In fact, we observed that the incidence of GI cancer was lower in individuals who used the drugs compared to nonusers. These findings suggest a potential beneficial effect of these drugs on cancer risk, likely attributed to their ability to improve digestive function.

Dopamine agonists and risk of lung cancer in patients with restless legs syndrome

PURPOSE

To examine the association between long-term use of dopamine agonists (DAs) and the risk of lung cancer in patients with restless legs syndrome (RLS).

METHODS

We conducted a retrospective cohort study using Optum Clinformatics® database. We included adults ≥40 years diagnosed with RLS during the study period (1/2006-12/2016). Follow-up started with the first RLS diagnosis and ended on the earliest of: incident diagnosis of lung cancer, end of enrollment in the database or end of the study period. The exposure of interest was cumulative duration of DAs use, measured in a time-varying manner. We constructed a multivariable Cox regression model to estimate HRs and 95% CIs for the association between lung cancer and cumulative durations of DA use, adjusting for potential confounding variables.

RESULTS

We identified 295 042 patients with a diagnosis of RLS. The mean age of the cohort was 62.9; 66.6% were women and 82.3% were white. The prevalence of any DA exposure was 40.3%. Compared to the reference group (no use and ≤1 year), the crude HRs for lung cancer were 1.16 (95% CI 0.99-1.36) and 1.14 (95% CI 0.86-1.51) for 1-3 years and >3 years of cumulative DA use, respectively. The adjusted HR for lung cancer was 1.05 (95% CI 0.88-1.25) for 1-3 years and 1.02 (95% CI 0.76-1.37) for >3 years of cumulative DA use, respectively.

CONCLUSIONS

At typical doses for the clinical management of RLS, long-term DA use was not associated with risk of lung cancer.

Adverse events and drug-drug interactions of sodium glucose co-transporter 2 inhibitors in patients treated for heart failure

INTRODUCTION

Sodium glucose co-transporter 2-inhibitors (SGLT2-I), antihyperglycemic agents, are increasingly prescribed in chronic heart failure (CHF). Their risk for drug-drug interactions (DDI) seems low. Safety-data derive mainly from diabetes-patients. This review aims to summarize adverse-events (AE) and DDI of the SGLT2-I dapagliflozin, empagliflozin and sotagliflozin in patients with CHF.

AREAS COVERED

Literature-search-terms in PubMed were 'adverse event/drug-drug interaction' and 'heart failure AND 'dapagliflozin' OR 'empagliflozin' OR 'sotagliflozin.'AEreported in randomized controlled trials (RCT) comprisegenitaland urinary-tract infections, hypotension, ketoacidosis, renal impairment, hypoglycemia, limb-amputations, Fournier's gangrene, bone-fractures, hepatopathy, pancreatitis, diarrhea, malignancy and venous thromboembolism. Their incidence is largely unknown, since they were not consistently evaluated in RCT of CHF. Further AE from meta-analyses, pharmacovigilance reports, case-series and case-reports include erythrocytosis, hypertriglyceridemia, myopathy, sarcopenia, skin problems, ventricular tachycardia, and urinary retention. The maximal observation period of RCT in CHF was 26 months.DDI were mainly studied in healthy volunteers for 3-8 days. In CHF or diabetes-patients, DDI were reported with interleukin-17-inhibitors, linezolid, lithium, tacrolimus, valproate, angiotensin-receptor-neprilysin-inhibitors and intravenous iron.

EXPERT OPINION

Guidelines recommend treatment with SGLT2-I for CHF but no data on AE during long-term therapy and only little information on DDI are available, which stresses the need for further research. Evidence-based recommendations for ketoacidosis-prevention are desirable.

PPIs and gastric cancer: any causal relationship?

Hydrochloric acid is crucial in gastric physiology. In 1978 cimetidine, the first H2 antagonist of histamine receptors on the gastric parietal cell was introduced into therapy, inducing acid. Lasting the years, several studies focused on the potential relationship between inducing hypo-achlorhydria and risk of developing gastric cancer. In 1988 omeprazole, the first proton pump inhibitor, entered therapy. In 1996, Kuipers underlined the danger of progression of chronic atrophic gastritis in subjects taking PPIs. In 2018, one paper from Korea and an another on from Sweden suggested a possible relationship between long-term PPI therapy and the development of gastric cancer. Over the years, several articles, meta-analyzes and population based  focused on relationship between long-term of PPI use and the onset of gastric cancer, with conflicting results. As reported, the presence of bias in the collection of cases, in particular concerning the evaluation of the H.p. status and presence of atrophic gastritis and intestinal metaplasia in subjects treated with PPI, can lead to noticeable errors in the results and conclusions, as demonstrated in the literature by exhaustive methodological studies of pharmacoepidemiology. A possible bias in the collection of case histories is due to the fact that PPIs are often administered to dyspeptic patients, among which there are patients already carriers of gastric neoplasia: the so-called inverse causality.  Literature data, amended by methodological bias (sampling errors, lack of comparative assessment of Hp status and atrophic gastritis) NOT support a causal relationship between long-term PPIs therapy and the onset of gastric cancer.

The Application of Lag Times in Cancer Pharmacoepidemiology: A Narrative Review

With the increasing utilization of medications worldwide, coupled with the increasing availability of long-term data, there is a growing opportunity and need for robust studies evaluating drug-cancer associations. One methodology of importance in such studies is the application of lag times. In this review, we discuss the main reasons for using lag times. Namely, we discuss the typically long latency period of cancer concerning both tumor promoter and initiator effects and outline why cancer latency is a key consideration when choosing a lag time. We also discuss how the use of lag times can help reduce protopathic and detection bias. Finally, we present practical advice for implementing lag periods. In general, we recommend that researchers consider the information that generated the hypothesis as well as clinical and biological knowledge to inform lag period selection. In addition, given that latency periods are usually unknown, we also advocate that researchers examine multiple lag periods in sensitivity analyses as well as duration analyses and flexible modeling approaches.

Healthcare system engagement and algorithm-identified cancer incidence following initiation of a new medication

PURPOSE

Implausibly high algorithm-identified cancer incidence within a new user study after medication initiation may result from increased healthcare utilization (HU) around initiation ("catch-up care") that increases diagnostic opportunity. Understanding the relationships between HU prior to and around initiation and subsequent cancer rates and timing is important to avoiding protopathic bias.

METHODS

We identified a cohort of 417 458 Medicare beneficiaries (2007-2014) aged ≥66 initiating an antihypertensive (AHT) after ≥180 days of non-use. Initiators were stratified into groups of 0, 1, 2-3, and ≥4 outpatient visits (OV) 60-360 days before initiation. We calculated algorithm-identified colorectal cancer (aiCRC) rates stratified by OVs and time since AHT initiation: (0-90, 91-180, 181-365, 366-730, and 731+ days). We summarized HU -360/+60 days around AHT initiation by aiCRC timing: (0-29, 30-89, 90-179, and ≥180 days).

RESULTS

AiCRC incidence (311 per 100 000 overall) peaked in the first 0-90 days, was inversely associated with HU before initiation, and stabilized ≥180 days after AHT initiation. Catch-up care was greatest among persons with aiCRCs identified <30 days in follow-up. Catch-up care magnitude decreased as time to the aiCRC date increased, with aiCRCs identified ≥180 days after AHT initiation exhibiting similar HU compared with the full cohort.

CONCLUSION

Lower HU before-and increased HU around AHT initiation-seem to drive excess short-term aiCRC incidence. Person-time and case accrual should only begin when incidence stabilizes. When comparison groups within a study differ by HU, outcome-detection bias may exist. Similar observations may exist in other settings when typical HU is delayed (e.g., cancer screening during SARS-CoV-2).

Association of metformin use and survival in patients with cutaneous melanoma and diabetes

BACKGROUND

Metformin use has been associated with improved survival in patients with different types of cancer, but research regarding the effect of metformin on cutaneous melanoma (CM) survival is sparse and inconclusive.

OBJECTIVES

To investigate the association between metformin use and survival among patients with CM and diabetes.

METHODS

All adult patients with a primary invasive CM between 2007 and 2014 were identified in the Swedish Melanoma Registry and followed until death, or end of follow-up on 31 December 2017 in this population-based cohort study. Patients with both CM and type 2 diabetes mellitus were assessed further. Overall survival (OS) and melanoma-specific survival (MSS) were the primary endpoints. Cox proportional hazard models estimating crude and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were used comparing peridiagnostic use vs. nonuse of metformin. Dose response was evaluated based on defined daily doses.

RESULTS

Among a total of 23 507 patients, 1162 patients with CM and type 2 diabetes mellitus were included in the final cohort, with a median follow-up time of 4.1 years (interquartile range 2.4-6.1). Peridiagnostic metformin use was associated with a significantly decreased risk of death by any cause (HR 0.68, 95% CI 0.57-0.81). Cumulative pre- and postdiagnostic metformin use was also associated with improved OS: the HR for prediagnostic use was 0.90 (95% CI 0.86-0.95) for every 6 months of use and the HR for postdiagnostic use ranged from 0.98 (95% CI 0.97-0.98) for 0-6 months to 0.59 (0.49-0.70) for 24-30 months of use. No association was found for metformin use and MSS.

CONCLUSIONS

Metformin use was associated with improved OS in patients with CM and diabetes regardless of timing (pre-, post- or peridiagnostic use) and followed a dose-response pattern. However, further research regarding the underlying mechanisms is warranted.

Testosterone therapy and cancer risks among men in the SEER-Medicare linked database

BACKGROUND

We examined associations between two forms of testosterone therapy (TT) and risks of seven cancers among men.

METHODS

SEER-Medicare combines cancer registry data from the Surveillance, Epidemiology, and End Results programme with Medicare claims. Our population-based case-control study included incident cancer cases diagnosed between 1992-2015: prostate (n = 130,713), lung (n = 105,466), colorectal (n = 56,433), bladder (n = 38,873), non-Hodgkin lymphoma (n = 17,854), melanoma (n = 14,241), and oesophageal (n = 9116). We selected 100,000 controls from a 5% random sample of Medicare beneficiaries and used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

TT was associated with lower risk of distant-stage prostate cancer (injection/implantation OR = 0.72, 95% CI: 0.60-0.86; topical OR = 0.50, 95% CI: 0.24-1.03). We also observed inverse associations for distant-stage colorectal cancer (injection/implantation OR = 0.75, 95% CI: 0.62-0.90; topical OR = 0.11, 95% CI: 0.05-0.24). Risks of distant-stage colorectal and prostate cancers decreased with time after initiating TT by injection/implantation. By contrast, TT was positively associated with distant-stage melanoma (injection/implantation OR = 1.70, 95% CI: 1.37-2.11). TT was not associated with bladder cancer, oesophageal cancer, lung cancer or non-Hodgkin lymphoma.

CONCLUSION

TT was inversely associated with distant-stage prostate and colorectal cancers but was positively associated with distant-stage melanoma. These observations may suggest an aetiologic role for TT or the presence of residual confounding.

Association between ranitidine use with potential NDMA impurities and risk of cancer in Korea

N-Nitrosodimethylamine (NDMA) detected above the acceptable level in ranitidine products has been a great global concern. To examine the risk of cancer among people treated with ranitidine, we conducted a cohort study using the National Health Insurance Service-National Sample Cohort data (2002-2015) of South Korea. Patients were aged 40 or above as of January 2004 and began receiving ranitidine or other histamine-2 receptor antagonist (H2RA), active comparator, without a history of H2RAs prescription during the prior 2-years. The lag time was designated up to 6 years. The outcomes were an overall incident cancer risk and the risk of major single cancers during the follow-up. The association between ranitidine use and cancer risk was examined by Cox regression model. After exclusion and propensity score matching, 25,360 patients were available for analysis. The use of ranitidine was not associated with the overall cancer risk and major individual cancers [overall cancer: incidence rate per 1000 person-years, 2.9 vs 3.0 among the ranitidine users and other H2RAs users, respectively; adjusted hazard ratio (HR) and 95% confidence interval (95% CI) for all cancers, 0.98 (0.81-1.20)]. The higher cumulative exposure to ranitidine did not increase the cancer risk. Given the insufficient follow-up period, these findings should be interpreted carefully.

Dihydropyridine Calcium Channel Blockers and Risk of Pancreatic Cancer: A Population-Based Cohort Study

Background Recent studies have reported that dihydropyridine calcium channel blockers (dCCBs) may increase the risk of pancreatic cancer, but these studies had methodological limitations. We thus aimed to determine whether dCCBs are associated with an increased risk of pancreatic cancer compared with thiazide diuretics, a clinically relevant comparator. Methods and Results We conducted a new user, active comparator, population-based cohort study using the UK Clinical Practice Research Datalink. We identified new users of dCCBs and new users of thiazide diuretics between 1990 and 2018, with follow-up until 2019. Cox proportional hazards models were used to estimate hazard ratios (HRs) with 95% CIs for pancreatic cancer, comparing dCCBs with thiazide diuretics. Models were weighted using standardized morbidity ratio weights based on calendar time-specific propensity scores. We also conducted secondary analyses by cumulative duration of use, time since initiation, and individual drugs and assessed for the presence of effect modification by age, sex, smoking status, body mass index, history of chronic pancreatitis, and diabetes. The cohort included 344 480 initiators of dCCBs and 357 968 initiators of thiazide diuretics, generating 3 360 745 person-years of follow-up. After a median follow-up of 4.5 years, the weighted incidence rate per 100 000 person-years was 37.2 (95% CI, 34.1-40.4) for dCCBs and 39.4 (95% CI, 36.1-42.9) for thiazide diuretics. Overall, dCCBs were not associated with an increased risk of pancreatic cancer (weighted HR, 0.93; 95% CI, 0.80-1.09). Similar results were observed in secondary analyses. Conclusions In this large, population-based cohort study, dCCBs were not associated with an increased risk of pancreatic cancer compared with thiazide diuretics. These findings provide reassurance regarding the long-term pancreatic cancer safety of these drugs.

Cancer-specific mortality in breast cancer patients with hypothyroidism: a UK population-based study

PURPOSE

Epidemiological studies have indicated a higher prevalence of hypothyroidism in breast cancer patients, possibly related to shared risk factors and breast cancer treatments. However, few studies have evaluated how hypothyroidism impacts survival outcomes in breast cancer patients. We aimed to determine the association between hypothyroidism and breast cancer-specific and all-cause mortality.

METHODS

We conducted a population-based study using the Scottish Cancer Registry to identify women diagnosed with breast cancer between 2010 and 2017. A matched comparison cohort of breast cancer-free women was also identified. Using hospital diagnoses and dispensed prescriptions for levothyroxine, we identified hypothyroidism diagnosed before and after breast cancer diagnosis and determined associations with breast cancer-specific and all-cause mortality. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) adjusted for potential confounders.

RESULTS

A total of 33,500 breast cancer patients were identified, of which 3,802 had hypothyroidism before breast cancer diagnosis and 565 patients went on to develop hypothyroidism after. Breast cancer patients had higher rates of hypothyroidism compared with cancer-free controls (HR 1.14, 95% CI 1.01-1.30). Among breast cancer patients, we found no association between hypothyroidism (diagnosed before or after) and cancer-specific mortality (before: HR 0.99, 95% CI 0.88-1.12, after: HR 0.97, 95% CI 0.63-1.49). Similar associations were seen for all-cause mortality.

CONCLUSION

In a large contemporary breast cancer cohort, there was little evidence that hypothyroidism, either at diagnosis or diagnosed after breast cancer, was associated with cancer-specific or all-cause mortality.

Dose-dependent relation between metformin and the risk of hormone receptor-positive, her2-negative breast cancer among postmenopausal women with type-2 diabetes

PURPOSE

Metformin has demonstrated a chemoprotective effect in breast cancer but there is limited evidence on the effect of cumulative exposure to metformin and the risk of hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR + /HER2-) breast cancer. This study assessed this risk with dose and intensity of metformin in postmenopausal women with type-2 diabetes mellitus (T2DM).

METHODS

This nested case-control study used the Surveillance, Epidemiology, and End Results-Medicare data (2008-2015). Cohort entry was the date of incident T2DM diagnosis. Cases were those diagnosed with HR + /HER2- breast cancer (event date) as their first/only cancer. Non-cancer T2DM controls were matched using variable-ratio-matching. Cumulative dose and average intensity of metformin were measured during the 1-year lookback period. Dose(mg) was categorized as: (1)0, (2)0-30,000, (3)30,001-136,000, (4)136,001-293,000, and (5) > 293,000, and intensity(mg/day) as: 0, 1-500, and > 500. Covariates were conceptualized using the Andersen Behavioral Model. Conditional logistic regression was used to assess the risk of HR + /HER2- breast cancer with metformin-use.

RESULTS

There were 690 cases and 2747 controls. The median duration of T2DM was 1178 days in controls and 1180 days in cases. Higher cumulative dose categories: 4 (adjusted odds ratio(aOR) = 0.72, 95% CI 0.55-0.95,p = 0.02), and 5 (OR = 0.60, 95% CI 0.42-0.85,p < 0.01) had significantly lower odds of HR + /HER2- breast cancer compared to category 0. The highest intensity category of metformin had 39% lower odds of HR + /HER2- breast cancer (OR = 0.61, 95% CI 0.46-0.82,p < 0.01) compared to the 0 mg/day group.

CONCLUSIONS

Higher metformin exposure was associated with reduced risk of HR + /HER2- breast cancer, adding to the evidence supporting metformin's chemoprotective effect.

Identification of Drug-Cancer Associations: A Nationwide Screening Study

The main tool in drug safety monitoring, spontaneous reporting of adverse effects, is unlikely to detect delayed adverse drug effects including cancer. Hypothesis-free screening studies based on administrative data could improve ongoing drug safety monitoring. Using Danish health registries, we conducted a series of case-control studies by identifying individuals with incident cancer in Denmark from 2001 to 2018, matching each case with 10 population controls on age, sex, and calendar time. ORs were estimated using conditional logistic regression accounting for matching factors, educational level, and selected comorbidities. A total of 13,577 drug-cancer associations were examined for individual drugs and 8,996 for drug classes. We reviewed 274 drug-cancer pairs where an association with high use and a cumulative dose-response pattern was present. We classified 65 associations as not readily attributable to bias of which 20 were established as carcinogens by the International Agency for Research on Cancer and the remaining 45 associations may warrant further study. The screening program identified drugs with known carcinogenic effects and highlighted a number of drugs that were not established as carcinogens and warrant further study. The effect estimates in this study should be interpreted cautiously and will need confirmation targeted epidemiologic and translational studies.

Significance

This study provides a screening tool for drug carcinogenicity aimed at hypothesis generation and explorative purposes. As such, the study may help to identify drugs with unknown carcinogenic effects and, ultimately, improve drug safety as part of the ongoing safety monitoring of drugs.

Use of Proton Pump Inhibitors and Risk of Pancreatic Cancer: A Nationwide Case-Control Study Based on the French National Health Data System (SNDS)

BACKGROUND

Only a few studies investigated the association between proton pump inhibitor (PPI) use and pancreatic cancer, with inconsistent results. Moreover, these studies had a number of methodologic limitations. Our objective was to assess this association in a nationwide case-control study.

METHODS

We used the French National Health Data System (SNDS), covering 99% of the French population since 2006. Incident cases of pancreatic cancer, identified between 2014 and 2018, were matched with up to four controls on year of birth, sex, frequency of hospitalization within 8 years prior to index date, and department of residence. Associations between PPIs and pancreatic cancer were estimated using conditional logistic regression models adjusted for sociodemographic characteristics, risk factors of pancreatic cancer (including diabetes mellitus, tobacco-related diseases, and morbid obesity), and other comorbidities.

RESULTS

A total of 23,321 cases of pancreatic cancer (mean age, 69.8 years; 51.7% males) and 75,937 matched controls were included. Overall, 77.8% of cases and 75.5% of controls were PPI ever users. Ever (vs. never) PPI use was associated with an increased risk of pancreatic cancer [adjusted OR (aOR) = 1.05, 95% confidence interval (CI), 1.01-1.09]. A dose-response relationship was observed [1-30 cumulative defined daily dose (cDDD): aOR = 0.92, 95% CI, 0.87-0.97; 31-180 cDDD: aOR = 1.05, 95% CI, 1.00-1.11; 181-1,080 cDDD: aOR = 1.18, 95% CI, 1.12-1.24; >1,080 cDDD: aOR = 1.17, 95% CI, 1.10-1.23].

CONCLUSIONS

On the basis of these findings, a slight increase in the risk of pancreatic cancer associated with high cumulative doses of PPIs cannot be excluded.

IMPACT

Given the overuse of PPIs, efforts should be continued to limit treatments to appropriate indications and durations.

Antiherpetic drugs: a potential way to prevent Alzheimer's disease?

Background

Considering the growing body of evidence suggesting a potential implication of herpesviruses in the development of dementia, several authors have questioned a protective effect of antiherpetic drugs (AHDs) which may represent a new means of prevention, well tolerated and easily accessible. Subsequently, several epidemiological studies have shown a reduction in the risk of dementia in subjects treated with AHDs, but the biological plausibility of this association and the impact of potential methodological biases need to be discussed in more depth.

Methods

Using a French medico-administrative database, we assessed the association between the intake of systemic AHDs and the incidence of (i) dementia, (ii) Alzheimer’s disease (AD), and (iii) vascular dementia in 68,291 subjects over 65 who were followed between 2009 and 2017. Regarding potential methodological biases, Cox models were adjusted for numerous potential confounding factors (including proxies of sociodemographic status, comorbidities, and use of healthcare) and sensitivity analyses were performed in an attempt to limit the risk of indication and reverse causality biases.

Results

9.7% of subjects (n=6642) had at least one intake of systemic AHD, and 8883 incident cases of dementia were identified. Intake of at least one systemic AHD during follow-up was significantly associated with a decreased risk of AD (aHR 0.85 95% confidence interval [0.75–0.96], p=0.009) and, to a lesser extent with respect to p values, to both dementia from any cause and vascular dementia. The association with AD remained significant in sensitivity analyses. The number of subjects with a regular intake was low and prevented us from studying its association with dementia.

Conclusions

Taking at least one systemic AHD during follow-up was significantly associated with a 15% reduced risk of developing AD, even after taking into account several potential methodological biases. Nevertheless, the low frequency of subjects with a regular intake questions the biological plausibility of this association and highlights the limits of epidemiological data to evaluate a potential protective effect of a regular treatment by systemic AHDs on the incidence of dementia

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-021-00950-0.

Low-dose aspirin and incidence of lung carcinoma in patients with chronic obstructive pulmonary disease in Hong Kong: A cohort study

BACKGROUND

Evidence suggests that chronic obstructive pulmonary disease (COPD) is associated with a higher risk of lung carcinoma. Using a territory-wide clinical electronic medical records system, we investigated the association between low-dose aspirin use (≤160 mg) among patients with COPD and incidence of lung carcinoma and the corresponding risk of bleeding.

METHODS AND FINDINGS

This is a retrospective cohort study conducted utilizing Clinical Data Analysis Reporting System (CDARS), a territory-wide database developed by the Hong Kong Hospital Authority. Inverse probability of treatment weighting (IPTW) was used to balance baseline covariates between aspirin nonusers (35,049 patients) with new aspirin users (7,679 patients) among all eligible COPD patients from 2005 to 2018 attending any public hospitals. The median age of the cohort was 75.7 years (SD = 11.5), and 80.3% were male. Competing risk regression with Cox proportional hazards model were performed to estimate the subdistribution hazard ratio (SHR) of lung carcinoma with low-dose aspirin and the associated bleeding events. Of all eligible patients, 1,779 (4.2%, 1,526 and 253 among nonusers and users) were diagnosed with lung carcinoma over a median follow-up period of 2.6 years (interquartile range [IQR]: 1.4 to 4.8). Aspirin use was associated with a 25% lower risk of lung carcinoma (SHR = 0.75, 95% confidence interval [CI] 0.65 to 0.87, p = <0.001) and 26% decrease in lung carcinoma-related mortality (SHR = 0.74, 95% CI 0.64 to 0.86, p = <0.001). Subgroup analysis revealed that aspirin was beneficial for patients aged above or below 75 years, but was also beneficial among populations who were male, nondiabetic, and nonhypertensive. Aspirin use was not associated with an increased risk of upper gastrointestinal bleeding (UGIB) (SHR = 1.19, 95% CI 0.94 to 1.53, p = 0.16), but was associated with an increased risk of hemoptysis (SHR = 1.96, 95% CI 1.73 to 2.23, p < 0.001). The main limitations of the study were (i) that one group of patients may be more likely to seek additional medical attention, although this was partially mitigated by the use of propensity score analysis; and (ii) the observational nature of the study renders it unable to establish causality between aspirin use and lung carcinoma incidence.

CONCLUSIONS

In this study, we observed that low-dose aspirin use was associated with a lower risk of lung carcinoma and lung carcinoma-related mortality among COPD patients. While aspirin was not associated with an increased risk of UGIB, the risk of hemoptysis was elevated.

Incidence of malignancy in multiple sclerosis: A cohort study in the Danish Multiple Sclerosis Registry

Background

The association between multiple sclerosis and malignancy is controversial and a current appraisal is needed.

Objective

To determine the incidence of malignancy in patients with multiple sclerosis compared with the general population and in relation to disease-modifying therapy.

Methods

Patients with multiple sclerosis (1995 – 2015) were matched by birth year and sex to individuals without multiple sclerosis in the general population. Patients with multiple sclerosis initiating disease-modifying therapy were evaluated using landmark period analysis. Malignancy risk was assessed by incidence rates, incidence rate ratios, and standardised incidence ratios.

Results

The standardised incidence ratio of any malignancy (excluding non-melanoma skin cancer) in patients with multiple sclerosis (n = 10,557) was 0.96 (95% CI 0.88 – 1.06), and there was no increased incidence of specific malignancy types compared with the general population cohort (n = 103,761). At the 48-month landmark period, the age-adjusted incidence per 100,000 person-years of any malignancy (excluding non-melanoma skin cancer) was 436.7 (95% CI 361.0 – 512.4) in patients newly treated with immunomodulator-only and 675.1 (95% CI 130.4 – 1219.9) in patients newly treated with immunosuppressant-only.

Conclusions

There was no increased incidence of malignancy overall or by type in patients with multiple sclerosis compared neither with the general population nor in relation to disease-modifying therapy.

Maternal Medication Use and Childhood Cancer in Offspring-Systematic Review and Considerations for Researchers

Cancer is an important cause of childhood mortality, yet the etiology is largely unknown. A combination of pre- and postnatal factors is thought to be implicated, including maternal medication use. We aimed to provide: 1) a systematic review of peer-reviewed publications on associations between maternal medication use and childhood cancer, with a focus on study design and methodology; and 2) suggestions for how to increase transparency, limit potential biases, and improve comparability in studies on maternal medication use and childhood cancer. We conducted a systematic search in the PubMed, Embase, Scopus, Cochrane, and Web of Science databases to June 8, 2020. Altogether, 112 studies were identified. The reviewed studies were heterogeneous in study design, exposure, and outcome classification. In 21 studies (19%), the outcome was any childhood cancer. Of the 91 papers that reported on specific types of cancer, 62% did not report the cancer classification system. The most frequently investigated medication groups were sex hormones (46 studies, excluding fertility medications), and antiinfectives (37 studies). Suggestions for strengthening future pharmacoepidemiologic studies on maternal medication use and childhood cancer relate to choice of cancer classification system, exposure windows, and methods for identification of, and control for, potential confounders.

Antipsychotic use and risk of breast cancer in women with schizophrenia: a nationwide nested case-control study in Finland

BACKGROUND

Breast cancer is more common in female patients with schizophrenia than in the general population. It is not known whether treatment with prolactin-increasing antipsychotics contributes to increased odds of breast cancer.

METHODS

We used Finnish nationwide registers of hospital treatment, prescription drug purchases, and cancer diagnoses to do a nested case-control study. Of women with schizophrenia, those with breast cancer (cases) were matched by age and duration of illness with five women without cancer (controls). Cases and controls were aged 18-85 years and exclusion criteria were any previous cancer diagnoses, receipt of organ transplant, mastectomy, or diagnosis of HIV. The main analysis was the association between cumulative exposure to prolactin-increasing drugs and breast cancer. The analyses were done with conditional logistic regression, by adjusting for comorbid conditions and concomitant medications. Ethnicity data were not available.

FINDINGS

Of 30 785 women diagnosed with schizophrenia between 1972 and 2014, 1069 were diagnosed with breast cancer between Jan 1, 2000, and Dec 31, 2017. Compared with 5339 matched controls, 1-4 years cumulative exposure (adjusted odds ratio [OR] 0·95, 95% CI 0·73-1·25) or 5 or more years exposure (adjusted OR 1·19, 0·90-1·58) to prolactin-sparing antipsychotics (including clozapine, quetiapine, or aripiprazole) was not associated with an increased risk of breast cancer in comparison with minimal exposure (<1 year). When compared with less than 1 year of exposure to prolactin-increasing antipsychotics (all other antipsychotics), 1-4 years of exposure was not associated with an increased risk, but exposure for 5 or more years was associated with an increased risk (adjusted OR 1·56 [1·27-1·92], p<0·001). The risk for developing lobular adenocarcinoma associated with long-term use of prolactin-increasing antipsychotics (adjusted OR 2·36 [95% CI 1·46-3·82]) was higher than that of developing ductal adenocarcinoma (adjusted OR 1·42 [95% CI 1·12-1·80]).

INTERPRETATION

Long-term exposure to prolactin-increasing, but not to prolactin-sparing, antipsychotics is significantly associated with increased odds of breast cancer. Monitoring prolactinemia and addressing hyperprolactinemia is paramount in women with schizophrenia being treated with prolactin-increasing antipsychotics.

FUNDING

Finnish Ministry of Social Affairs and Health.

Use of incretin-based drugs and risk of cholangiocarcinoma: Scandinavian cohort study

AIMS/HYPOTHESIS

Concerns have been raised regarding a potential association of use of the incretin-based drugs dipeptidyl peptidase 4 (DPP4) inhibitors and glucagon-like peptide-1 (GLP-1)-receptor agonists with risk of cholangiocarcinoma. We examined this association in nationwide data from three countries.

METHODS

We used data from nationwide registers in Sweden, Denmark and Norway, 2007-2018, to conduct two cohort studies, one for DPP4 inhibitors and one for GLP-1-receptor agonists, to investigate the risk of incident cholangiocarcinoma compared with an active-comparator drug class (sulfonylureas). The cohorts included patients initiating treatment episodes with DPP4 inhibitors vs sulfonylureas, and GLP-1-receptor agonists vs sulfonylureas. We used Cox regression models, adjusted for potential confounders, to estimate hazard ratios from day 366 after treatment initiation to account for cancer latency.

RESULTS

The main analyses of DPP4 inhibitors included 1,414,144 person-years of follow-up from 222,577 patients receiving DPP4 inhibitors (median [IQR] follow-up time, 4.5 [2.6-7.0] years) and 123,908 patients receiving sulfonylureas (median [IQR] follow-up time, 5.1 [2.9-7.8] years) during which 350 cholangiocarcinoma events occurred. Use of DPP4 inhibitors, compared with sulfonylureas, was not associated with a statistically significant increase in risk of cholangiocarcinoma (incidence rate 26 vs 23 per 100,000 person-years; adjusted HR, 1.15 [95% CI 0.90, 1.46]; absolute rate difference 3 [95% CI -3, 10] events per 100,000 person-years). The main analyses of GLP-1-receptor agonists included 1,036,587 person-years of follow-up from 96,813 patients receiving GLP-1-receptor agonists (median [IQR] follow-up time, 4.4 [2.4-6.9] years) and 142,578 patients receiving sulfonylureas (median [IQR] follow-up time, 5.5 [3.2-8.1] years) during which 249 cholangiocarcinoma events occurred. Use of GLP-1-receptor agonists was not associated with a statistically significant increase in risk of cholangiocarcinoma (incidence rate 26 vs 23 per 100,000 person-years; adjusted HR, 1.25 [95% CI 0.89, 1.76]; absolute rate difference 3 [95% CI -5, 13] events per 100,000 patient-years).

CONCLUSIONS/INTERPRETATION

In this analysis using nationwide data from three countries, use of DPP4 inhibitors and GLP-1-receptor agonists, compared with sulfonylureas, was not associated with a significantly increased risk of cholangiocarcinoma.

Use of antidepressants and endometrial-cancer risk: a nationwide nested case-control study

BACKGROUND

Preclinical studies have suggested that antidepressant drugs may possess antineoplastic properties. In a nationwide case-control study, we examined the association between use of antidepressants and endometrial-cancer risk with a particular focus on selective serotonin reuptake inhibitors (SSRIs).

METHODS

From the Danish Cancer Registry, we identified all women with a histologically verified diagnosis of endometrial cancer between 2000 and 2016, and, for each woman, 15 age-matched controls. We obtained information on use of SSRIs, tricyclic antidepressants (TCAs) and other antidepressants based on records of filled prescriptions from the National Prescription Register. Using conditional logistic regression, we calculated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for associations between use of antidepressants and endometrial-cancer risk compared with non-use. In active comparator analyses, SSRI use was compared with TCA use.

RESULTS

The study population comprised 8164 cases and 122 432 controls. Compared with non-use, SSRI use was associated with an OR of 0.88 (95% CI 0.82-0.96) for endometrial cancer, whereas the association with TCA use was close to unity (OR 1.05, 95% CI 0.90-1.22). Use of other antidepressants yielded an OR of 0.86 (95% CI 0.71-1.03). We observed no apparent trends in associations according to cumulative amount. The inverse association with SSRI use persisted when compared with TCA use (OR 0.81, 95% CI 0.66-0.99).

CONCLUSIONS

Use of SSRIs was associated with a decreased risk of endometrial cancer, whereas no inverse association appeared with use of TCAs. The antineoplastic potential of SSRIs should be investigated in future studies.

No association between chronic use of ranitidine, compared with omeprazole or famotidine, and gastrointestinal malignancies

BACKGROUND

In 2019, the United States Food and Drug Administration detected above-regulation levels of the human carcinogen N-nitrosodimethylamine (NDMA) in ranitidine, resulting in a complete removal of the medication from the market. NDMA is known to cause gastrointestinal malignancies in animal models.

AIM

To determine if patients who were receiving ranitidine have a higher risk of developing cancers of the digestive tract compared to patients taking other anti-reflux medications.

METHODS

Using the nationwide database IBM Explorys, patients taking ranitidine were compared to patients on either famotidine or omeprazole. Incidence data of new malignancies of the oesophagus, stomach, liver, pancreas, and colon/rectum were obtained in 1-year intervals for up to 10 years. Two multivariable logistic regression models were used to calculate odds ratios (ORs), one adjusting for common risk factors for each cancer studied, and the other for demographic factors.

RESULTS

Patients on ranitidine who were compared to patients on famotidine had ORs of 0.51(95% CI 0.43-0.60), 0.43(95% CI 0.36-0.51), 0.39(95% CI 0.36-0.41), 0.54(95% CI 0.49-0.62), and 0.46(95% CI 0.43-0.49) of developing oesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers, respectively (P < 0.001). Patients on ranitidine compared to omeprazole had ORs of 0.62(95% CI 0.52-0.72), 0.58(95% CI 0.49-0.68), 0.81 (95% CI 0.76-0.86), 0.68(95% CI 0.60-0.76), and 0.66(95% CI 0.62-0.70) of developing oesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers respectively (P < 0.001).

CONCLUSIONS

Use of ranitidine was not associated with an increased odds of developing gastrointestinal malignancies compared to omeprazole or famotidine use.

Tumor Necrosis Factor Inhibitors and the Risk of Cancer among Older Americans with Rheumatoid Arthritis

BACKGROUND

TNF inhibitors (TNFi) effectively treat rheumatoid arthritis but may increase patient risk of some malignancies, particularly lymphomas or skin cancers.

METHODS

We used Surveillance, Epidemiology, and End Results (SEER)-Medicare data to conduct a case-control study in patients with rheumatoid arthritis (2007-2015). Cases were individuals with a first cancer diagnosed in SEER registries (ages 66-99, 22 cancer sites, N = 10,263). Skin cancer cases [nonmelanoma skin cancer (NMSC, N = 501), basal cell carcinoma (BCC, N = 161), squamous cell carcinoma (SCC, N = 150)] and cancer-free controls (N = 30,475) were selected from Medicare beneficiaries residing in SEER areas. Cases and controls had prior Medicare claims-based evidence for rheumatoid arthritis, and TNFi exposure was ascertained from part B and part D claims. Logistic regression was used to estimate adjusted odds ratios (aOR).

RESULTS

TNFi exposure was present in 16.2% of controls and 12.8% to 33.7% of cancer cases, varying by site. TNFi use was associated with increased risk of NMSC overall (aOR 1.32, 95% confidence interval 1.06-1.63), non-Hodgkin lymphoma (NHL) overall (1.28, 1.06-1.56) and, specifically, follicular lymphoma (2.63, 1.63-4.24). TNFi exposure was not associated with other SEER cancer sites, BCC or SCC specifically, or other common NHL subtypes.

CONCLUSIONS

Among older adults with rheumatoid arthritis, TNFi exposure was associated with elevated risk of NMSC and NHL, driven specifically by follicular lymphoma. Exposure was not associated with increased risk for other cancer sites.

IMPACT

Our results support a role for TNF in lymphomagenesis. Given the association with NMSC, patients initiating TNFi therapy may benefit from skin cancer screening and sun protection measures.

Proton pump inhibitors and survival in patients with colorectal cancer: a Swedish population-based cohort study

BACKGROUND

Proton pump inhibitors (PPIs) are associated with microbiome changes of the gut, which in turn may affect the progression of colorectal cancer (CRC). This study aims to assess the associations between PPI use and all-cause and CRC-specific mortality.

METHODS

We selected all patients registered in the Swedish Prescribed Drug Registry who were diagnosed with CRC between 2006 and 2012 (N = 32,411, 54.9% PPI users) and subsequently followed them through register linkage to the Swedish Causes of Death Registry until December 2013. PPI users were patients with ≥1 post-diagnosis PPI dispensation. Time-dependent Cox-regression models were performed with PPI use as time-varying exposure.

RESULTS

Overall 4746 (14.0%) patients died, with an aHR of 1.38 (95% CI 1.32-1.44) for all-cause mortality comparing PPI users with PPI nonusers. Higher-magnitude associations were observed among male, cancer stage 0-I, rectal cancer and patients receiving CRC surgery. The PPI-all-cause mortality association was also more pronounced comparing new users to non-users (aHR = 1.47, 95%CI 1.40-1.55) than comparing continuous users to non-users (aHR = 1.32, 95%CI 1.24-1.39). The risk estimates for CRC-specific mortality comparing PPI users to PPI nonusers were similar to those for all-cause mortality.

CONCLUSION

PPI use after the CRC diagnosis was associated with increased all-cause and CRC-specific mortality.

Statin associated lower cancer risk and related mortality in patients with heart failure

Aims 

Patients with heart failure (HF) have an increased risk of incident cancer. Data relating to the association of statin use with cancer risk and cancer-related mortality among patients with HF are sparse.

Methods and results 

Using a previously validated territory-wide clinical information registry, statin use was ascertained among all eligible patients with HF (n = 87 102) from 2003 to 2015. Inverse probability of treatment weighting was used to balance baseline covariates between statin nonusers (n = 50 926) with statin users (n = 36 176). Competing risk regression with Cox proportional-hazard models was performed to estimate the risk of cancer and cancer-related mortality associated with statin use. Of all eligible subjects, the mean age was 76.5 ± 12.8 years, and 47.8% was male. Over a median follow-up of 4.1 years (interquartile range: 1.6–6.8), 11 052 (12.7%) were diagnosed with cancer. Statin use (vs. none) was associated with a 16% lower risk of cancer incidence [multivariable adjusted subdistribution hazard ratio (SHR) = 0.84; 95% confidence interval (CI), 0.80–0.89]. This inverse association with risk of cancer was duration dependent; as compared with short-term statin use (3 months to <2 years), the adjusted SHR was 0.99 (95% CI, 0.87–1.13) for 2 to <4 years of use, 0.82 (95% CI, 0.70–0.97) for 4 to <6 years of use, and 0.78 (95% CI, 0.65–0.93) for ≥6 years of use. Ten-year cancer-related mortality was 3.8% among statin users and 5.2% among nonusers (absolute risk difference, −1.4 percentage points [95% CI, −1.6% to −1.2%]; adjusted SHR = 0.74; 95% CI, 0.67–0.81).

Conclusion 

Our study suggests that statin use is associated with a significantly lower risk of incident cancer and cancer-related mortality in HF, an association that appears to be duration dependent.

Use of Proton Pump Inhibitors vs Histamine 2 Receptor Antagonists for the Risk of Gastric Cancer: Population-Based Cohort Study

INTRODUCTION

Proton pump inhibitors (PPIs) are commonly prescribed medications. Long-term use of PPIs has been suspected to have a provocative effect on gastric cancer. This study was to determine the association between PPI vs histamine 2 receptor antagonist (H2RA) use and the risk of gastric cancer in a region where the risk of this malignancy is high.

METHODS

A population-based cohort study using the Korean National Health Insurance Services Database. The participants with first prescription of PPIs and H2RA with normal esophagogastroduodenoscopy finding from 2004 through 2015 were collected. Among them, 50% of participants were systematic stratified randomly sampled. There were 122,118 users of PPIs or H2RAs who use medication more than cumulative defined daily dose of 180 days. The users were followed up from long-term use threshold until gastric cancer, death from non-gastric cancer cause, gastric surgery, or study end (December 2017).

RESULTS

After calculating propensity score weights, we included 39,799 PPI and 38,967 H2RA users. Among the new PPI and H2RA users, we identified 411 cases of incident gastric cancer from 182,643 person-years of follow-up observation and 397 cases from 178,846 person-years of follow-up observation, respectively. Compared with H2RA users, PPI users did not experience significantly different gastric cancer incidence (adjusted hazard ratio, 1.01; 95% confidence interval, 0.88-1.16; P = 0.89). Sensitivity analyses confirmed that gastric cancer incidence did not differ between PPI and H2RA users.

DISCUSSION

In this large study, long-term treatment with PPIs vs H2RAs did not show higher risk of gastric cancer even in a high-risk region.

The effect of medications associated with drug-induced pancreatitis on pancreatic cancer risk: A nested case-control study of routine Scottish data

BACKGROUND

Inflammation plays a role in pancreatic cancer. Many medications cause pancreatic inflammation, with some leading to a diagnosis of drug-induced pancreatitis (DIP), but few studies have examined these medications and pancreatic cancer risk. We therefore investigated the associations between pancreatic cancer risk and commonly-prescribed medicines for which there is strongest evidence of DIP.

METHODS

A nested case-control study was undertaken using the Primary Care Clinical Informatics Unit Research database containing general practice (GP) records from Scotland. Pancreatic cancer cases, diagnosed between 1999 and 2011, were identified and matched with up to five controls (based on age, gender, GP practice and date of registration). Medicines in the highest category of evidence for DIP, based on a recent systematic review, and used by more than 2 % of controls were identified. Odds ratios (OR) and 95 % confidence intervals (CI) for associations with pancreatic cancer were calculated using conditional logistic regression after adjusting for comorbidities.

RESULTS

There were 1,069 cases and 4,729 controls. Thirteen medicines in the highest category of evidence for DIP were investigated. There was little evidence of an association between any of these medications and pancreatic cancer risk apart from metronidazole (adjusted OR 1.69, 95 % CI 1.18, 2.41) and ranitidine (adjusted OR 1.37, 95 %CI 1.10, 1.70). However, no definitive exposure-response relationships between these medicines and cancer risk were observed.

CONCLUSIONS

There is little evidence that commonly-prescribed medicines associated with inflammation of the pancreas are also associated with pancreatic cancer. These findings should provide reassurance to patients and prescribing clinicians.

A systematic assessment of the association between frequently prescribed medicines and the risk of common cancers: a series of nested case-control studies

BACKGROUND

Studies systematically screening medications have successfully identified prescription medicines associated with cancer risk. However, adjustment for confounding factors in these studies has been limited. We therefore investigated the association between frequently prescribed medicines and the risk of common cancers adjusting for a range of confounders.

METHODS

A series of nested case-control studies were undertaken using the Primary Care Clinical Informatics Unit Research (PCCIUR) database containing general practice (GP) records from Scotland. Cancer cases at 22 cancer sites, diagnosed between 1999 and 2011, were identified from GP records and matched with up to five controls (based on age, gender, GP practice and date of registration). Odds ratios (OR) and 95% confidence intervals (CI) comparing any versus no prescriptions for each of the most commonly prescribed medicines, identified from prescription records, were calculated using conditional logistic regression, adjusting for comorbidities. Additional analyses adjusted for smoking use. An association was considered a signal based upon the magnitude of its adjusted OR, p-value and evidence of an exposure-response relationship. Supplementary analyses were undertaken comparing 6 or more prescriptions versus less than 6 for each medicine.

RESULTS

Overall, 62,109 cases and 276,580 controls were included in the analyses and a total of 5622 medication-cancer associations were studied across the 22 cancer sites. After adjusting for comorbidities 2060 medicine-cancer associations for any prescription had adjusted ORs greater than 1.25 (or less than 0.8), 214 had a corresponding p-value less than or equal to 0.01 and 118 had evidence of an exposure-dose relationship hence meeting the criteria for a signal. Seventy-seven signals were identified after additionally adjusting for smoking. Based upon an exposure of 6 or more prescriptions, there were 118 signals after adjusting for comorbidities and 82 after additionally adjusting for smoking.

CONCLUSIONS

In this study a number of novel associations between medicine and cancer were identified which require further clinical and epidemiological investigation. The majority of medicines were not associated with an altered cancer risk and many identified signals reflected known associations between medicine and cancer.

Use of Immunomodulating Drugs and Risk of Cutaneous Melanoma: A Nationwide Nested Case-Control Study

Purpose

Cutaneous melanoma is among the fastest growing malignancies in Norway and ultraviolet radiation (UVR) exposure is the primary environmental risk factor. Immunomodulating drugs can increase skin photosensitivity and suppress immune responses, and by such mechanisms influence melanoma risk. We, therefore, aimed to examine the associations between use of immunomodulating drugs and melanoma risk, at a nationwide population level.

Patients and Methods

In the Cancer Registry of Norway, we identified all cases aged 18-85 with a first primary cutaneous melanoma diagnosed in 2007-2015 (n=12,106). These were matched to population controls from the Norwegian National Registry 1:10 (n=118,564), on sex and year of birth using risk set sampling. Information on prescribed drugs (2004-2015) was obtained by linkage to the Norwegian Prescription Database (NorPD). Conditional logistic regression was used to estimate rate ratios (RRs) and 95% confidence intervals (CIs) for associations between use of immunomodulating drugs (immunosuppressants and corticosteroids) and melanoma risk, adjusted for ambient UVR and other drug use.

Results

Compared with ≤1 prescription, use of ≥8 prescriptions of immunosuppressants was associated with increased risk of melanoma (RR 1.50, 95% CI 1.27, 1.77). Similar associations were found for subgroups of immunosuppressants: drugs typically prescribed to organ transplant recipients (OTRs) (RR 2.02, 95% CI 1.35, 3.03) and methotrexate (RR 1.27, 95% CI 1.04, 1.55). Similar results were found for high levels of cumulative doses and across all histological subtypes. Use of corticosteroids was not associated with melanoma risk.

Conclusion

We found a positive association between use of immunosuppressants and melanoma risk, with the highest risk seen for drugs prescribed to OTRs. Knowledge about this risk increase is important for physicians and users of these drugs, for intensified surveillance, awareness and cautious sun exposure.

Association Between Angiotensin II Receptor Blockers and the Risk of Lung Cancer Among Patients With Hypertension From the Korean National Health Insurance Service-National Health Screening Cohort

Objectives:

The objective of this study was to estimate the risk of lung cancer in relation to angiotensin II receptor blocker (ARB) use among patients with hypertension from the Korean National Health Insurance Service-National Health Screening Cohort.

Methods:

We conducted a retrospective cohort study of patients with hypertension who started to take antihypertensive medications and had a treatment period of at least 6 months. We calculated the weighted hazard ratios (HRs) and their 95% confidence intervals (CIs) of lung cancer associated with ARB use compared with calcium channel blocker (CCB) use using inverse probability treatment weighting.

Results:

Among a total of 60 469 subjects with a median follow-up time of 7.8 years, 476 cases of lung cancer were identified. ARB use had a protective effect on lung cancer compared with CCB use (HR, 0.75; 95% CI, 0.59 to 0.96). Consistent findings were found in analyses considering patients who changed or discontinued their medication (HR, 0.50; 95% CI, 0.32 to 0.77), as well as for women (HR, 0.56; 95% CI, 0.34 to 0.93), patients without chronic obstructive pulmonary disease (HR, 0.75; 95% CI, 0.56 to 1.00), never-smokers (HR, 0.64; 95% CI, 0.42 to 0.99), and non-drinkers (HR, 0.69; 95% CI, 0.49 to 0.97). In analyses with different comparison antihypertensive medications, the overall protective effects of ARBs on lung cancer risk remained consistent.

Conclusions:

The results of the present study suggest that ARBs could decrease the risk of lung cancer. More evidence is needed to establish the causal effect of ARBs on the incidence of lung cancer.

Risk of Cancer in Association with Ranitidine and Nizatidine vs Other H2 Blockers: Analysis of the Japan Medical Data Center Claims Database 2005-2018

INTRODUCTION

In September 2019, ranitidine and nizatidine were suggested to contain N-nitrosodimethylamine, a carcinogenic substance. People have since been concerned about the potential impact of ranitidine/nizatidine use on the risk of cancer.

OBJECTIVE

The objective of this study was to investigate the risk of cancer among people receiving ranitidine or nizatidine compared with other histamine 2 receptor antagonists (H2 blockers) [cimetidine, famotidine, roxatidine, and lafutidine].

METHODS

In the Japan Medical Data Center claims database (comprising people aged < 75 years) from 2005 to 2018, we identified new adult users of H2 blockers and classified them into ranitidine/nizatidine users and other H2 blocker users. We estimated the incidence of cancer diagnosis in each group and conducted a multivariable Cox regression analysis.

RESULTS

We identified 113,745 new users of ranitidine/nizatidine (median age 41.2 years [interquartile range 31.7-51.1]; 49.1% men; median follow-up 2.4 years [1.1-4.5]) and 503,982 new users of other H2 blockers (median age 40.9 years [31.1-51.2]; 51.0% men; median follow-up 2.3 years [0.9-4.2]). The incidence rate of cancer diagnosis was 6.39 (95% confidence interval 6.13-6.66) cases per 1000 person-years (top three sites: breast 14.8%; colorectal 14.6%; and stomach 11.5%) in the ranitidine/nizatidine group and 6.17 (6.05-6.30) cases per 1000 person-years (colorectal 14.7%; breast 13.5%; and stomach 11.2%) in the other H2 blockers group. The adjusted hazard ratio (ranitidine/nizatidine users vs other H2 blocker users) was 1.02 (0.98-1.07). The results were similar by follow-up length, by cancer site, and when ranitidine and nizatidine users were separately compared with the other H2 blockers group. By cumulative dose, the adjusted hazard ratio (95% confidence interval) was 1.03 (0.98-1.08) from 1 to 180 defined daily doses (DDDs), 1.00 (0.73-1.39) from 181 to 365 DDDs, 0.95 (0.61-1.48) from 366 to 730 DDDs, and 0.83 (0.45-1.55) at > 730 DDDs.

CONCLUSIONS

We found no evidence that ranitidine/nizatidine is associated with an increased risk of cancer, although further studies with more accurate measurement of exposure, inclusion of older people, and longer follow-up may be needed.

Real-world evidence: the devil is in the detail

Much has been written about real-world evidence (RWE), a concept that offers an understanding of the effects of healthcare interventions using routine clinical data. The reflection of diverse real-world practices is a double-edged sword that makes RWE attractive but also opens doors to several biases that need to be minimised both in the design and analytical phases of non-experimental studies. Additionally, it is critical to ensure that researchers who conduct these studies possess adequate methodological expertise and ability to accurately implement these methods. Critical design elements to be considered should include a clearly defined research question using a causal inference framework, choice of a fit-for-purpose data source, inclusion of new users of a treatment with comparators that are as similar as possible to that group, accurately classifying person-time and deciding censoring approaches. Having taken measures to minimise bias 'by design', the next step is to implement appropriate analytical techniques (for example propensity scores) to minimise the remnant potential biases. A clear protocol should be provided at the beginning of the study and a report of the results after, including caveats to consider. We also point the readers to readings on some novel analytical methods as well as newer areas of application of RWE. While there is no one-size-fits-all solution to evaluating RWE studies, we have focused our discussion on key methods and issues commonly encountered in comparative observational cohort studies with the hope that readers are better equipped to evaluate non-experimental studies that they encounter in the future. Graphical abstract.

Low-dose aspirin use and risk of head and neck cancer-A Danish nationwide case-control study

Results concerning a potential preventive effect of aspirin on head and neck cancer (HNC) are conflicting. We examined the association between low-dose aspirin use and HNC risk overall and by degree of human papillomavirus association in a nested case-control study using nationwide registries. Cases (n = 12 389) were all Danish residents diagnosed with primary HNC (2000-2015). Age- and sex-matched population controls (n = 185 835) were selected by risk-set-sampling. Using conditional logistic regression, we estimated multivariable-adjusted odds ratios and 95% confidence intervals for HNC associated with low-dose aspirin use (≥2 prescriptions). No association was observed between low-dose aspirin ever-use and overall HNC (odds ratio: 1.03, 95% confidence interval: 0.97-1.10). Estimates remained neutral according to patterns of use. Low-dose aspirin use appeared to slightly decrease HNC risk among the eldest (71-84 y), independently of human papillomavirus association, while slightly increase HNC risk among younger age groups (30-60, 61-70 y), driven by an increased risk of oral cancer. However, no consistent patterns in risk estimates were found according to duration and consistency of low-dose aspirin use in the age-stratified analyses.

Reporting and variability of constructing medication treatment episodes in pharmacoepidemiology studies: A methodologic systematic review using the case study of DPP-4 inhibitors and cardiovascular outcomes

PURPOSE

In pharmacoepidemiologic studies, estimating medication adherence, persistence, and exposure patterns is critical. Constructing medication treatment episodes from prescription claims data involves assumptions related to grace period, carry-over, and lag effect, but there are no guidelines for these assumptions. We evaluated reporting and variability of these parameters in pharmacoepidemiology studies, using a case study of antihyperglycemic medications and major adverse cardiovascular events (MACE).

METHODS

We conducted a systemic review using MEDLINE and EMBASE for studies published prior to January 2, 2020 comparing the risk of MACE between dipeptidyl peptidase 4 (DPP-4) inhibitors and active comparators. We extracted study characteristics and results, including grace period, carry-over, and lag effect. Risk of bias was assessed by the Newcastle-Ottawa scale, and assessments for prevalent user, immortal time, time lag, and time window biases.

RESULTS

A total of 14/1850 studies identified were included. Grace period was not reported in 5 (35.7%) studies and ranged from 0 days to 180 days when reported. Carry-over was not reported in 10 studies (71.4%). Lag effect was not reported in nine (71.4%) studies and ranged from 0 days to 180 days when reported. No studies conducted sensitivity analyses examining the effects of these assumptions on study findings. Predominant biases were inadequate follow-up time, comparability of cohorts, prevalent use, and lag time bias.

CONCLUSIONS

Use of grace period, carry-over, and lag effect were poorly reported and highly variable. Future pharmacoepidemiology studies should improve reporting, justify ranges for these parameters, and conduct sensitivity analyses to evaluate effects of these assumptions.

ACE (Angiotensin-Converting Enzyme) Inhibitors/Angiotensin Receptor Blockers Are Associated With Lower Colorectal Cancer Risk: A Territory-Wide Study With Propensity Score Analysis

Whether ACE (angiotensin-converting enzyme) inhibitors and angiotensin receptor blockers modify colorectal cancer risk remains controversial. We aimed to determine association between their use and colorectal cancer risk after a negative baseline colonoscopy. This is a territory-wide retrospective cohort study recruiting patients aged ≥40 who had undergone colonoscopy between 2005 and 2013. Exclusion criteria included colorectal cancer detected <6 months of index colonoscopy, prior colorectal cancer, inflammatory bowel disease, and prior colectomy. The primary outcome was colorectal cancer diagnosed between 6 and 36 months after index colonoscopy. Sites of colorectal cancer were categorized as proximal (proximal to splenic flexure) and distal cancer. The adjusted hazard ratio of colorectal cancer with ACE inhibitor/angiotensin receptor blocker use (≥180-day use within 5 years before index colonoscopy) was derived by propensity score regression adjustment of 23 covariates (including patient's factors, concurrent medication use, and endoscopy center's performance). Of 187 897 eligible patients, 30 856 (16.4%) were ACE inhibitors/angiotensin receptor blocker users. Eight hundred fifty-four (0.45%) developed colorectal cancer between 6 and 36 months after index colonoscopy (proximal cancer: 147 [17.2%]). These drugs were associated with lower risk of colorectal cancer that developed <3 years after index colonoscopy (adjusted hazard ratio, 0.78 [95% CI, 0.64-0.96]), but not colorectal cancer that developed >3years (adjusted hazard ratio, 1.18 [95% CI, 0.88-1.57]); every single year increase in the drug use was associated with 5% reduction in adjusted hazard ratio risk. ACE inhibitors/angiotensin receptor blocker were associated with a lower colorectal cancer risk in a duration-response manner.