A population-based cohort study in Taiwan--use of insulin sensitizers can decrease cancer risk in diabetic patients?

Pioglitazone, Bladder Cancer and the Presumption of Innocence

BACKGROUND

Thiazolidinediones are potent exogenous agonists of PPAR-γ, which augment the effects of insulin to its cellular targets and mainly at the level of adipose tissue. Pioglitazone, the main thiazolidinedione in clinical practice, has shown cardiovascular and renal benefits in patients with type 2 diabetes, durable reduction of glycated hemoglobulin levels, important improvements of several components of the metabolic syndrome and beneficial effects of non-alcoholic fatty liver disease.

OBJECTIVE

Despite all of its established advantages, the controversy for an increased risk of developing bladder cancer, combined with the advent of newer drug classes that achieved major cardiorenal effects have significantly limited its use spreading a persistent shadow of doubt for its future role.

METHODS

Pubmed, Google and Scope databases have been thoroughly searched and relevant studies were selected.

RESULTS

This paper explores thoroughly both in vitro and in vivo (animal models and humans) studies that investigated the possible association of pioglitazone with bladder cancer.

CONCLUSION

Currently the association of pioglitazone with bladder cancer cannot be based on solid evidence. This evidence cannot justify its low clinical administration, especially in the present era of individualised treatment strategies. Definite clarification of this issue is imperative and urgently anticipated from future high quality and rigorous pharmacoepidemiologic research, keeping in mind its unique mechanism of action and its significant pleiotropic effects.

Antidiabetic Medications and the Risk of Prostate Cancer in Patients with Diabetes Mellitus: A Systematic Review and Meta-analysis

BACKGROUND

Antidiabetic medications (ADMs) may modify prostate cancer (PCa) risk in patients with diabetes mellitus (DM). Accordingly, the current study assessed the possible associations between ADMs and the risk of PCa in diabetics.

METHODS

A systematic literature search (PubMed, Embase and Cochrane Library) identified studies evaluating the associations between ADMs and incidence of PCa. A meta-analysis followed PRISMA was performed using odds ratio (OR) with 95% confidence interval (CI) as effect measures.

RESULTS

In total of 47 studies involving 3,094,152 patients with diabetes were included. Results of meta-analysis of the observational studies suggested no significant association between metformin, thiazolidinediones, sulfonylureas, insulin or dipeptidyl peptidase-4 inhibitors administration and the risk of PCa (All p-values > 0.05). Separate analysis of randomized controlled trials (RCTs) revealed a significant reduction in PCa risk with thiazolidinediones (OR = 0.55, p = 0.04) or glucagon-like peptide-1 receptor agonists (GLP-1RA) administration (OR = 0.53, p = 0.006), whereas no significant association was found in SGLT2 inhibitors (p = 0.3).

CONCLUSION

Thiazolidinediones or GLP-1RA administration may have benefits in PCa based on RCTs, however, further research is needed to confirm these findings.

Thiazolidinediones, alpha-glucosidase inhibitors, meglitinides, sulfonylureas, and hepatocellular carcinoma risk: A meta-analysis

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related death worldwide. Effects of second-line oral antidiabetic medications on incident HCC risk in individuals with type 2 diabetes mellitus remain unclear. This study evaluated associations between sulfonylureas, thiazolidinediones, meglitinides and alpha-glucosidase inhibitors, and incident HCC risk.

METHODS

We systematically reviewed all studies on PubMed, Embase and Web of Science databases. Studies were included if they documented: (1) exposure to oral antidiabetic medication classes; (2) HCC incidence; (3) relative risks/odds ratios (OR) for HCC incidence. Eight eligible observational studies were identified. We performed random-effects meta-analyses to calculate pooled adjusted ORs (aORs) and 95% confidence intervals (CI).

RESULTS

Thiazolidinedione use (7 studies, 280,567 participants, 19,242 HCC cases) was associated with reduced HCC risk (aOR = 0.92, 95% CI = 0.86-0.97, I² = 43%), including among Asian subjects (aOR = 0.90, 95% CI = 0.83-0.97), but not Western subjects (aOR = 0.95, 95% CI = 0.87-1.04). Alpha-glucosidase inhibitor use (3 studies, 56,791 participants, 11,069 HCC cases) was associated with increased HCC incidence (aOR = 1.08; 95% CI = 1.02-1.14, I² = 21%). Sulfonylurea use (8 studies, 281,180 participants, 19,466 HCC cases) was associated with increased HCC risk in studies including patients with established liver disease (aOR = 1.06, 95% CI = 1.02-1.11, I² = 75%). Meglitinide use (4 studies, 58,237 participants, 11,310 HCC cases) was not associated with HCC incidence (aOR = 1.19; 95% CI = 0.89-1.60, I² = 72%).

CONCLUSIONS

Thiazolidinedione use was associated with reduced HCC incidence in Asian individuals with diabetes. Alpha-glucosidase inhibitor or sulfonylurea use was associated with modestly increased HCC risk; future research should determine whether those agents should be avoided in patients with chronic liver disease.

Development of a prediction model for pancreatic cancer in patients with type 2 diabetes using logistic regression and artificial neural network models

Objectives

Patients with type 2 diabetes (T2DM) are suggested to have a higher risk of developing pancreatic cancer. We used two models to predict pancreatic cancer risk among patients with T2DM.

Methods

The original data used for this investigation were retrieved from the National Health Insurance Research Database of Taiwan. The prediction models included the available possible risk factors for pancreatic cancer. The data were split into training and test sets: 97.5% of the data were used as the training set and 2.5% of the data were used as the test set. Logistic regression (LR) and artificial neural network (ANN) models were implemented using Python (Version 3.7.0). The F₁, precision, and recall were compared between the LR and the ANN models. The areas under the receiver operating characteristic (ROC) curves of the prediction models were also compared.

Results

The metrics used in this study indicated that the LR model more accurately predicted pancreatic cancer than the ANN model. For the LR model, the area under the ROC curve in the prediction of pancreatic cancer was 0.727, indicating a good fit.

Conclusion

Using this LR model, our results suggested that we could appropriately predict pancreatic cancer risk in patients with T2DM in Taiwan.

Development of a Prediction Model for Colorectal Cancer among Patients with Type 2 Diabetes Mellitus Using a Deep Neural Network

Objectives: Observational studies suggested that patients with type 2 diabetes mellitus (T2DM) presented a higher risk of developing colorectal cancer (CRC). The current study aims to create a deep neural network (DNN) to predict the onset of CRC for patients with T2DM. Methods: We employed the national health insurance database of Taiwan to create predictive models for detecting an increased risk of subsequent CRC development in T2DM patients in Taiwan. We identified a total of 1,349,640 patients between 2000 and 2012 with newly diagnosed T2DM. All the available possible risk factors for CRC were also included in the analyses. The data were split into training and test sets with 97.5% of the patients in the training set and 2.5% of the patients in the test set. The deep neural network (DNN) model was optimized using Adam with Nesterov’s accelerated gradient descent. The recall, precision, F₁ values, and the area under the receiver operating characteristic (ROC) curve were used to evaluate predictor performance. Results: The F₁, precision, and recall values of the DNN model across all data were 0.931, 0.982, and 0.889, respectively. The area under the ROC curve of the DNN model across all data was 0.738, compared to the ideal value of 1. The metrics indicate that the DNN model appropriately predicted CRC. In contrast, a single variable predictor using adapted the Diabetes Complication Severity Index showed poorer performance compared to the DNN model. Conclusions: Our results indicated that the DNN model is an appropriate tool to predict CRC risk in patients with T2DM in Taiwan.

The influence of diabetes and antidiabetic medications on the risk of pancreatic cancer: a nationwide population-based study in Korea

This study investigated the effects of diabetes and antidiabetic medications on the risk of pancreatic cancer(PaC). We extracted data on Koreans with newly diagnosed diabetes and selected age- and sex-matched controls provided by the National Health Insurance Corporation. Incident PaC was defined as a new registration in the Korea Central Cancer Registry under ICD-10 C25 with admission history until 2015. During 19,429,617.1 person-years, 8,589 PaCs were identified in 1,005,409 subjects for diabetes group and 4,021,636 subjects for control group. The diabetes group showed more than a two-fold risk for PaC compared with the control group. Among antidiabetic medications, metformin, thiazolidinedione, and dipeptidyl peptidase-4 inhibitor exposure was associated with decreased risk for future PaC(hazard ratio[95% confidence interval] = 0.86[0.77–0.96], 0.82[0.68–0.98], 0.57[0.51–0.64], respectively), whereas sulfonylurea and insulin exposure was related to increased risk(hazard ratio[95% CI] = 1.73[1.57–1.91], 2.86[1.43–5.74], respectively) compared to subjects with no drug exposure. Moreover, subjects with dual exposure history to metformin plus thiazolidinedione or metformin plus dipeptidyl peptidase-4 inhibitor had a lower risk of PaC compared to metformin-only treated subjects. In conclusion, Korean adults with diabetes are at higher risk of PaC compared with nondiabetic individuals, and this risk may be modified by antidiabetic medications.

Pioglitazone use in patients with diabetes and risk of bladder cancer: a systematic review and meta-analysis

Pioglitazone has been reported to increase the risk of bladder cancer but the conclusions of published clinical studies are confusing. We conducted a systematic review and meta-analysis of all eligible randomized controlled trial (RCT) studies and observational studies, in order to identify a more precise relationship between pioglitazone and risk of bladder cancer. We searched for publications up to January 24, 2018, in PubMed, EMBASE, Scopus, Web of Science, Cochrane register, and Chinese National Knowledge Infrastructure databases, and the references of the retrieved articles and relevant reviews were also checked. Relative risk and 95% confidence interval (CI) were used to assess this correlation. A dose-related meta-analysis was performed as well. Data on RCT studies showed a null association between pioglitazone and bladder cancer. The pooled RR estimates of the 12 included studies illustrated that pioglitazone is associated with a 14% increased risk of bladder cancer (95% CI 1.03-1.26). No evidence of publication bias was detected. In the dose effect analysis, patients who used a higher dose of pioglitazone had an increased risk of bladder cancer. In conclusion, this meta-analysis indicated that pioglitazone is associated with an increased risk of bladder cancer. Further research should be conducted to confirm our findings and reveal the potential biological mechanisms.

Thiazolidinedione therapy and breast cancer risk in diabetic women: A systematic review and meta-analysis

Rising experimental evidence suggests that thiazolidinediones (TZDs) exert a protective effect on breast cancer. However, studies concerning this issue were inconsistent and limited. Hence, we performed a meta-analysis with data from currently available studies to evaluate the effect of TZDs on breast cancer risk among diabetic women. We comprehensively searched for all pertinent studies addressing TZDs use and breast cancer risk published before January 1, 2016, in PubMed, Clinical Trials, and Cochrane Library. Data synthesis was performed in a random-effects model using Stata version 12.0 (Stata Corp, College Station, Texas). Fourteen independent studies were eventually selected in this meta-analysis, including 5 randomized controlled clinical trials (RCTs), 7 cohort studies, and 2 case-control studies. No significant associations of TZD use and risk of breast cancer were observed in the RCTs (pooled risk ratio [RR]: 0.77, 95% confidence interval (CI), 0.39-1.53, I²  = 26%) or case-control studies (pooled odds ratio, 0.99, 95% CI, 0.76-1.28, I²  = 31%). A 19% reduction in breast cancer risk (pooled RR: 0.81, 95% CI, 0.66-0.99, I²  = 72%) was found in the cohort studies. However, after removing the study with the smallest event number and the greatest effect size, the association became nonsignificant with greatly decreased heterogeneity (pooled RR: 0.94, 95% CI, 0.86-1.03, I²  = 16%). This meta-analysis did not find any significant association between TZDs use and risk of breast cancer among diabetic women.

Thiazolidinediones and risk of colorectal cancer in patients with diabetes mellitus: A meta-analysis

BACKGROUND/AIMS

A growing body of evidence has suggested that thiazolidinediones (TZDs) potentially reduce the risk of colorectal cancer (CRC). This study aimed to evaluate the effect of TZDs on CRC risk in patients with diabetes mellitus (DM).

PATIENTS AND METHODS

A systematic search of electronic databases was performed for studies evaluating the exposure to TZDs and reporting CRC risk in diabetic patients. Pooled estimates with 95% confidence intervals (CIs) were estimated using fixed or random effects models.

RESULTS

A total of 10 observational studies reporting more than 18,972 CRC cases in 2,470,768 DM patients were included. Meta-analysis showed a 9% reduction in CRC risk associated with TZDs use in all studies [relative risk (RR) =0.91, 95% CI = 0.84-0.99, P = 0.03] and cohort studies (RR = 0.89, 95% CI = 0.80-0.99, P = 0.04), respectively. However, such effect was not shown in case-control studies. In subgroup analyses, lower CRC risk was found in Asian population (RR = 0.40, 95% CI = 0.29-0.53, P = 0.00), and a trend toward lower CRC risk was observed in US population (RR = 0.94, 95% CI = 0.88-1.01, P = 0.08). CRC risk was significantly modified with non-pioglitazone TZD use (RR = 0.88, 95% CI = 0.82-0.95, P = 0.00), but not with pioglitazone use (RR = 0.95, 95% CI = 0.89-1.01, P = 0.11). No significant difference was observed with cancer site (colon or rectum). There was considerable inherent heterogeneity across studies, partly explained by study location.

CONCLUSIONS

This meta-analysis supports a protective association between TZDs use and CRC risk in patients with DM. Future well-designed prospective studies with larger cohorts would be needed to understand this association better.

Association between insulin therapy and risk of liver cancer among diabetics: a meta-analysis of epidemiological studies

As the results of the association between insulin therapy and risk of liver cancer among diabetics have been inconsistent in epidemiological studies, we conducted a meta-analysis to quantify this issue. Data of relevant epidemiological studies were collected by searching articles in PubMed, Web of Science, and Embase till 29 June 2017. Random-effects models were employed to combine study-specific risks. Five cohort studies and nine case-control studies were included in our meta-analysis with 285 008 patients with diabetes mellitus and 4329 liver cancer cases. When we compared insulin-use group with noninsulin use group in patients with diabetes mellitus, we observed a statistically significant association between insulin therapy and liver cancer, with an overall relative risk of 1.90 (95% confidence interval: 1.44-2.50, I=76.1%). We did not find heterogeneity between subgroups stratified by study characteristics and adjusted confounders, except for subgroups related to 'follow-up years' of cohort studies. The combined estimate was robust across sensitivity analysis, and no publication bias was detected. Our results indicated that insulin therapy was associated with elevated incidence of liver cancer among diabetics. Given the high prevalence of diabetes, avoiding excess or unnecessary insulin use to control the blood glucose may offer a potential public health benefit in reducing liver cancer risk. Further studies are warranted to investigate the types, doses, and treatment duration of insulin use in large sample size or cohort of diabetic patients.

Pregnancy Incidence in Female Nasopharyngeal Carcinoma Survivors of Reproductive Age: A Population-Based Study

This study evaluated the pregnancy incidence in female nasopharyngeal carcinoma (NPC) survivors of reproductive age.In a nationwide cohort, 2816 female patients 15 to 50 years of age from 1998 to 2010 were identified from the Taiwan National Health Insurance Research database. Comorbidities, complications during pregnancy, and delivery status were recorded. All patients were followed up until a diagnosis of pregnancy, withdrawal from the National Health Insurance system, or December 31, 2011.Overall, 155 patients (incidence rate [IR] = 9.50) were pregnant in the NPC group, whereas 251 patients (IR = 12.80) were pregnant in the non-NPC group. The cumulative incidence of pregnancy in the NPC group was lower than that in the non-NPC group (incidence rate ratio = 0.74, 95% CI = 0.61-0.91). The adjusted hazard ratio of pregnancy in the NPC group was 0.79 with 95% CI = 0.61-0.96, compared with the non-NPC group.The incidence of pregnancy is significantly lower among female NPC survivors of reproductive age than among those without NPC.

Cancer risk in East Asian patients associated with acquired haemolytic anaemia: a nationwide population-based cohort study

BACKGROUND

This study investigated whether patients with acquired haemolytic anaemia (AHA) would have elevated cancer risk including that for non-haematological solid tumours. We further examined whether the cancer risk would be different between patients with autoimmune type AHA (AIHA) and patients of non-AIHA.

METHODS

Using nationwide population-based insurance claims data of Taiwan we identified a cohort of patients with AHA with no pre-existing cancer, (n = 3902) and a comparison cohort (n = 39020) without AHA, frequency-matched by gender, age, urbanization of residency and diagnosis date. Incidence and Cox method estimated adjusted hazard ratios (aHR) of cancers controlling covariates by the end of 2010 were calculated. Risks between patients with AIHA and non-AIHA were compared. Sensitivity analysis was carried out to measure the risk of cancer between patients with and without AHA by follow-up years.

RESULTS

Patients with AHA had a 90% greater incidence of cancer than controls, with an aHR of 1.78 (95% confidence interval (CI), 1.50-2.12)]. The overall aHRs of cancer for patients with AIHA and non-AIHA were 2.01 (95% CI, 1.56-2.59) and 1.87 (95% CI, 1.53-2.29), respectively, compared with the comparison cohort. The aHRs for lymphatic-haematopoietic malignancy were 19.5 and 9.59 in the AIHA and non-AIHA cohorts, respectively. No hazard of colorectal, lung, liver or breast cancer was significant.

CONCLUSIONS

There is a near 2-fold elevated risk for subsequent cancer in patients with AHA, particularly for lymphatic-haematopoietic malignancy, which is much greater for patients with AIHA than non-AIHA. These findings can help clinicians decide patient-centred personalized long-term management.

Diabetes mellitus increases the risk of colorectal neoplasia: An updated meta-analysis

OBJECTIVE

Recent studies proved that patients with diabetes were at significantly higher risk of developing colorectal cancer. However, the association between diabetes mellitus and the risk of colorectal adenoma remains undefined. Thus we conducted an updated meta-analysis to identify the association between diabetes mellitus and the risk of colorectal neoplasia including adenoma and cancer.

METHODS

We conducted a search in databases including Pubmed, Web of Science, EMBASE Databases, Cochrane CENTRAL, Wanfang Data, and CNKI database. Case-control and cohort studies were included. All articles were published before January 2015 and the quality of each study was evaluated by the Newcastle-Ottawa Scale. Odds ratios (ORs) or relative risks (RRs) and its corresponding 95% confidence intervals (CIs) for each study were calculated and summary relative risk estimates with corresponding 95% CIs were generated using the random-effects model. Heterogeneity and publication bias were assessed.

RESULTS

Twenty-nine articles including ten case-control studies and nineteen cohort studies were included in this meta-analysis. In a pooled analysis of all studies, diabetes mellitus was associated with increased risk of colorectal neoplasia (RR=1.35, 95% CI=1.28-1.42). The risk increased significantly for both colorectal cancer (RR=1.37, 95% CI=1.30-1.45) and adenoma (RR=1.26, 95% CI=1.11-1.44). Subgroup analyses on study design, gender, geographical region, and type of diabetes mellitus further evidenced these findings.

CONCLUSIONS

Diabetes mellitus was associated with an increased risk of colorectal neoplasia. Not only the increased risk of colorectal cancer but also the higher risk of adenoma was identified in patients with diabetes mellitus.

Statin Use Reduces Prostate Cancer All-Cause Mortality: A Nationwide Population-Based Cohort Study

Studies have suggested that statin use is related to cancer risk and prostate cancer mortality. We conducted a population-based cohort study to determine whether using statins in prostate cancer patients is associated with reduced all-cause mortality rates. Data were obtained from the Taiwan National Health Insurance Research Database. The study cohort comprised 5179 patients diagnosed with prostate cancer who used statins for at least 6 months between January 1, 1998 and December 31, 2010. To form a comparison group, each patient was randomly frequency-matched (according to age and index date) with a prostate cancer patient who did not use any type of statin-based drugs during the study period. The study endpoint was mortality. The hazard ratio (HR) and 95% confidence interval (CI) were estimated using Cox regression models. Among prostate cancer patients, statin use was associated with significantly decreased all-cause mortality (adjusted HR = 0.65; 95% CI = 0.60-0.71). This phenomenon was observed among various types of statin, age groups, and treatment methods. Analyzing the defined daily dose of statins indicated that both low- and high-dose groups exhibited significantly decreased death rates compared with nonusers, suggesting a dose-response relationship. The results of this population-based cohort study suggest that using statins reduces all-cause mortality among prostate cancer patients, and a dose-response relationship may exist.

Anti-diabetic medications do not influence risk of lung cancer in patients with diabetes mellitus: a systematic review and meta-analysis

OBJECTIVES

Several preclinical and observational studies have shown that anti-diabetic medications (ADMs) may modify the risk of lung cancer. We performed a systematic review and meta-analysis evaluating the effect of metformin, sulfonylureas (SUs), thiazolidinediones (TZDs), and insulin on the risk of lung cancer in patients with diabetes mellitus (DM).

MATERIALS AND METHODS

We conducted a systematic search of Pubmed and Web of Science, up to August 20, 2013. We also searched the Conference Proceedings Citation Index (CPCI) and China National Knowledge Infrastructure (CNKI) for abstracts from major meetings. Fixed or random effect pooled measures were selected based on heterogeneity among studies, which was evaluated using Q test and the I2 of Higgins and Thompson. Meta-regression was used to explore the sources of between-study heterogeneity. Publication bias was analyzed by Begg's funnel plot and Egger's regression test. Associations were assessed by odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of 15 studies (11 cohort, 4 case-control) were included in this meta-analysis. In observational studies no significant association between metformin (n=11 studies; adjusted OR=0.99, 95%CI: 0.87-1.12), SUs (n=5 studies; adjusted OR=0.98, 95%CI: 0.79-1.22), or TZDs (n=7 studies; adjusted OR=0.92, 95%CI: 0.75-1.13), insulin (n=6 studies; adjusted OR=1.13, 95%CI: 0.79-1.62) use and risk of developing lung cancer was noted. There was considerable inherent heterogeneity between studies not explained by study design, setting, or location.

CONCLUSIONS

Meta-analysis of existing studies does not support a protective or harmful association between ADMs use and risk of lung cancer in patients with DM. There was considerable heterogeneity across studies, and future, well-designed, prospective studies would be required for better understanding of any association.

Type 2 diabetes mellitus and risk of oral cancer and precancerous lesions: a meta-analysis of observational studies

OBJECTIVE

Associations between type 2 diabetes mellitus (type 2 DM) and risk of oral cancer and precancerous lesions have been reported with controversial findings. We performed a meta-analysis to explore these associations.

METHODS

We identified studies by a literature search of MEDLINE and EMBASE through May 31, 2014, and by searching the reference lists of pertinent articles. Summary relative risk (SRR) with 95% confidence interval (CI) was calculated with a random-effects model. Between- study heterogeneity was assessed using the Cochran's Q and I(2) statistics.

RESULTS

A total of 13 studies (4 case-control and 9 cohort studies) on the association between type 2 DM and oral cancer were included. Overall analysis found that compared with non-diabetic individuals, individuals with type 2 DM had a significantly elevated incidence of oral cancer (SRR=1.15, 95% CI: 1.02-1.29; Pheterogeneity=0.277, I(2)=15.4%; 10 studies). Subgroup analyses found that duration of follow-up (⩾11years) significantly altered this positive association. Type 2 DM was associated with increased oral cancer mortality (SRR=1.41, 95% CI: 1.16-1.72; 4 studies). Meta-analysis of the four case-control studies showed a positive association between type 2 DM and risk of oral precancerous lesions (SRR=1.85, 95%CI: 1.23-2.80; Pheterogeneity=0.038, I(2)=57.5%). No significant public bias was found across these studies.

CONCLUSIONS

These findings of this meta-analysis indicate that compared with non-diabetic individuals, individuals with type 2 DM have an elevated risk of oral cancer and precancerous lesions development.

Metformin and lung cancer risk of patients with type 2 diabetes mellitus: A meta-analysis

The association between metformin and the lung cancer risk of patients with type 2 diabetes mellitus (T2DM) remains controversial. Therefore, the present meta-analysis on epidemiological studies was performed to explore this issue. A comprehensive literature search was conducted for all the potential studies addressing metformin use and lung cancer risk by utilizing Pubmed, CBM and ISI Web of Science using the Mesh terms: 'Metformin,' or 'biguanides' and 'lung cancer,' or 'neoplasms'. The reference lists were also inspected. Eight observational studies, including 17,997 lung cancer patients, were eventually selected, which contained seven case-control and one cohort study. Compared to other antidiabetic agents, metformin was significantly associated with the 16% reduction of lung cancer risk in type 2 diabetic patients [relative risk (RR)=0.84; 95% confidence interval (95% CI), 0.73-0.97]. In the sensitivity analysis by separately excluding the study with a high weight or lower quality, the results did not materially change. Subsequently, subgroup analysis was performed on the type of study design, unadjusted or adjusted hazard ratio, quality of enrolled studies, duration of treatment, country and control drugs. The magnitude of lung cancer risk reduction was strengthened when compared to sulfonylureas (RR=0.79; 95% CI, 0.83-0.9), without significant heterogeneity (Q-value=2.98, P=0.085). In conclusion, the present analysis supported that the use of metformin significantly decreased the risk of lung cancer among patients with T2DM. However, further studies are required to confirm these findings.

CARING (CAncer Risk and INsulin analoGues): the association of diabetes mellitus and cancer risk with focus on possible determinants - a systematic review and a meta-analysis

Background:

Patients suffering from diabetes mellitus (DM) may experience an increased risk of cancer; however, it is not certain whether this effect is due to diabetes per se.

Objective:

To examine the association between DM and cancers by a systematic review and meta-analysis according to the PRISMA guidelines.

Data Sources:

The systematic literature search includes Medline at PubMed, Embase, Cinahl, Bibliotek.dk, Cochrane library, Web of Science and SveMed+ with the search terms: “Diabetes mellitus”, “Neoplasms”, and “Risk of cancer”.

Study Eligibility Criteria:

The included studies compared the risk of cancer in diabetic patients versus non-diabetic patients. All types of observational study designs were included.

Results:

Diabetes patients were at a substantially increased risk of liver (RR=2.1), and pancreas (RR=2.2) cancer. Modestly elevated significant risks were also found for ovary (RR=1.2), breast (RR=1.1), cervix (RR=1.3), endometrial (RR=1.4), several digestive tract (RR=1.1-1.5), kidney (RR=1.4), and bladder cancer (RR=1.1). The findings were similar for men and women, and unrelated to study design. Meta-regression analyses showed limited effect modification of body mass index, and possible effect modification of age, gender, with some influence of study characteristics (population source, cancer- and diabetes ascertainment).

Limitations:

Publication bias seemed to be present. Only published data were used in the analyses.

Conclusions:

The systematic review and meta-analysis confirm the previous results of increased cancer risk in diabetes and extend this to additional cancer sites. Physicians in contact with patients with diabetes should be aware that diabetes patients are at an increased risk of cancer.

Subsequent risk of nasopharyngeal carcinoma among patients with allergic rhinitis: a nationwide population-based cohort study

BACKGROUND

The purpose of this study was to examine the risk of nasopharyngeal carcinoma (NPC) after a diagnosis of allergic rhinitis.

METHODS

We identified 67,532 patients with allergic rhinitis (allergic rhinitis cohort) and a 135,064 control cohort with the same mean age and sex ratio by using a Taiwan Longitudinal Health Insurance Database (LHID) sample from 2000 to 2005.

RESULTS

After adjusting for the possible confounding factors of the study, the allergic rhinitis cohort had a 2.33-fold higher risk of developing NPC than did the comparison cohort. The frequency of allergic rhinitis visits was correlated with the risk of subsequent NPC. Patients with 4 or more allergic rhinitis visits per year were significantly associated with increasingly developing NPC risk.

CONCLUSION

Patients with allergic rhinitis might be associated with subsequent NPC in Taiwan. Those who had repeated visits for allergic rhinitis had even higher risk for NPC. Physicians should be aware of the link when assessing patients with allergic rhinitis.

Dose effect of thiazolidinedione on cancer risk in type 2 diabetes mellitus patients: a six-year population-based cohort study

WHAT IS KNOWN AND OBJECTIVE

Prior studies found that thiazolidinediones (TZDs) might have tumour-suppressor activity mediated through cell-cycle arrest, induction of apoptosis and inhibition of cell invasion. The main objective of this study was to investigate the effects of TZDs on the risk of cancer among patients with type 2 diabetes mellitus (DM).

METHODS

Patients diagnosed with DM between 1 January 1998 and 31 December 2002 were identified from the Longitudinal Health Insurance Database (LHID) within the Taiwan National Health Insurance (NHI) programme. Using Cox regression models, we assessed the association between prescribed TZDs and cancer risk, TZDs' dose effect and the association between TZDs and specific cancer types. Hazard ratios (HR) were adjusted for potential confounders (age, gender, income, Charlson score index, metformin and insulin use).

RESULTS AND DISCUSSION

The adjusted HRs for those prescribed TZD were 0·74 (95% CI 0·43-1·26, P = 0·27), 0·39 (95% CI 0·33-0·45, P < 0·001) and 0·49 (95% CI 0·27-0·89, P = 0·02), respectively, relative to non-DM patients, DM patients prescribed other anti-DM drugs besides TZDs and DM patients not prescribed any anti-DM drugs. In addition, the effects of TZDs were shown to be significantly dose dependent (P for trend < 0·001). The risk of breast, brain, colorectal, ear-nose-throat, kidney, liver, lung, lymphatic, prostate, stomach, and uterus cancer was significantly lower in those prescribed TZDs.

WHAT IS NEW AND CONCLUSIONS

The results showed a decrease in cancer risk in diabetic patients using TZD, and the association was dose dependent.

Paediatric head CT scan and subsequent risk of malignancy and benign brain tumour: a nation-wide population-based cohort study

Background:

To evaluate the possible association between paediatric head computed tomography (CT) examination and increased subsequent risk of malignancy and benign brain tumour.

Methods:

In the exposed cohort, 24 418 participants under 18 years of age, who underwent head CT examination between 1998 and 2006, were identified from the Taiwan National Health Insurance Research Database (NHIRD). Patients were followed up until a diagnosis of malignant disease or benign brain tumour, withdrawal from the National Health Insurance (NHI) system, or at the end of 2008.

Results:

The overall risk was not significantly different in the two cohorts (incidence rate=36.72 per 100 000 person-years in the exposed cohort, 28.48 per 100 000 person-years in the unexposed cohort, hazard ratio (HR)=1.29, 95% confidence interval (CI)=0.90–1.85). The risk of benign brain tumour was significantly higher in the exposed cohort than in the unexposed cohort (HR=2.97, 95% CI=1.49–5.93). The frequency of CT examination showed strong correlation with the subsequent overall risk of malignancy and benign brain tumour.

Conclusions:

We found that paediatric head CT examination was associated with an increased incidence of benign brain tumour. A large-scale study with longer follow-up is necessary to confirm this result.

Women with alopecia exhibit a higher risk for thyroid cancer: a nationwide cohort study

BACKGROUND

Several studies have investigated the relationship between alopecia and prostate cancer. However, little information is available regarding the relationship between alopecia and the risk of cancers in women.

OBJECTIVE

The purpose of this study was to evaluate the possible association between alopecia and thyroid cancer among Taiwanese women.

METHODS

We used data from the National Health Insurance system of Taiwan. The alopecia cohort comprised 4534 women, and each woman was randomly frequency matched by age, index month, and index year with 4 women from the general population without alopecia. A Cox proportional hazard regression analysis with Bonferroni correction was conducted to estimate the effects of alopecia on the risk of thyroid cancer.

RESULTS

In women with alopecia, the overall risk for developing cancer was 22% higher than for subjects without alopecia, but the difference was not significant [hazard ratio (HR) = 1.22, 97.5% confidence interval (97.5% CI) = 0.87-1.70]. However, the risk for developing thyroid cancer among women with alopecia was significantly higher (HR = 2.39, 97.5% CI = 1.05-5.42). Further analyses determined that the alopecia group had a higher incidence of Graves' disease, but not Hashimoto thyroiditis.

CONCLUSION

Although alopecia did not significantly increase cancer risks in women, we found that Taiwanese women with alopecia had a higher risk of developing thyroid cancer that is unlikely to be related to underlying thyroid diseases.

Reappraisal of the etiology of extracorpuscular non-autoimmune acquired hemolytic anemia in 2657 hospitalized patients with non-neoplastic disease

INTRODUCTION

Unlike autoimmune hemolytic anemia (AIHA), literature on the etiological study of non-autoimmune hemolytic anemia (non-AIHA) is scarce. The incidence and prevalence of non-AIHA in different geographic regions are largely unknown perhaps owing to the lack of perspective investigation and different profiles of etiologies from different geographic regions. We aimed to examine the real-world etiology or mechanisms of the non-hereditary non-AIHA from a nationwide population-based administrative claim database in Taiwan.

PATIENTS AND METHODS

The National Health Insurance Research Database of Taiwan was adopted for this research. The studied population was total inpatient claim records including both pediatric and adult patients, contributed by a population of 23 million insured individuals in Taiwan. From 2002 to 2008, we retrieved 3,903 patients having no pre-existing malignancy discharged after inpatient management for acquired hemolytic anemia, which was defined as coding in discharge diagnoses containing ICD-9-CM code 283. By contrast, ICD-9-CM code 282 and all of the sub-codes are for hereditary hemolytic anemias.

RESULTS

AIHA accounted for 32% of the total cases. Among 2,657 patients with non-AIHA, mechanical or microangiopathic mechanism accounted for 19% of cases; hemolytic-uremic syndrome (HUS) 4%, hemoglobinuria because of hemolysis from external causes such as paroxysmal nocturnal hemoglobinuria (PNH) and march hemoglobinuria 7%, and chronic idiopathic hemolytic anemia or other unspecified non-AIHA 69%. We looked further for specific etiology or mechanism for this group of patients with non-hereditary extrinsic non-AIHA (n = 2,657). The explanatory disease states or conditions were splenomegaly; alcohol use disorder (spur cell hemolysis); heart-valve prosthesis; malignant hypertension; disseminated intravascular coagulation; transfusion reaction; dengue fever-induced hemolytic anemia; direct parasitization; snake, lizard, or spider bite; and Wilson's disease with internal toxin mechanism. All these cases can explain up to 34.6% of all the non-hereditary extrinsic non-AIHA cases. Fragmentation hemolysis (HUS, heart-valve prosthesis, malignant hypertension, and disseminated intravascular coagulation) accounted for 7.4% of non-AIHA hospitalized patients with non-neoplastic disease.

CONCLUSIONS

This article is the first one to clearly demonstrate that the non-neoplastic-induced HUS requiring hospitalization cases in Taiwan, which has a population of over 23 million were 110 over a span of seven years, 16 cases per year. Although the etiologies of non-AIHA are well known and described in the literature, this work added the statistical percentages of the various etiologies of non-AIHA in Taiwan.

A review on thiazolidinediones and bladder cancer in human studies

There is a concern of an increased risk of bladder cancer associated with the use of thiazolidinediones, a class of oral glucose-lowering drugs commonly used in patients with type 2 diabetes with a mechanism of improving insulin resistance. Human studies on related issues are reviewed, followed by a discussion on potential concerns on the causal inference in current studies. Pioglitazone and rosiglitazone are discussed separately, and findings from different geographical regions are presented. Randomized controlled trials designed for primarily answering such a cancer link are lacking, and evidence from clinical trials with available data for evaluating the association may not be informative. Observational studies have been reported with the use of population-based administrative databases, single-hospital records, drug adverse event reporting system, and case series collection. Meta-analysis has also been performed by six different groups of investigators. These studies showed a signal of higher risk of bladder cancer associated with pioglitazone, especially at a higher cumulative dose or after prolonged exposure; however, a weaker signal or null association is observed with rosiglitazone. In addition, there are some concerns on the causal inference, which may be related to the use of secondary databases, biases in sampling, differential detection, and confounding by indications. Lack of full control of smoking and potential biases related to study designs and statistical approaches such as prevalent user bias and immortal time bias may be major limitations in some studies. Overlapping populations and opposing conclusions in studies using the same databases may be of concern and weaken the reported conclusions of the studies. Because randomized controlled trials are expensive and unethical in providing an answer to this cancer issue, observational studies are expected to be the main source in providing an answer in the future. Furthermore, international comparison studies using well-designed and uniform methodology to clarify the risk in specific sexes, ethnicities, and other subgroups and to evaluate the interaction with other environmental risk factors or medications will be helpful to identify patients at risk.