Sources of heterogeneity in case-control studies on associations between statins, ACE-inhibitors, and proton pump inhibitors and risk of pneumonia

The State of Use and Utility of Negative Controls in Pharmacoepidemiologic Studies

Uses of real-world data in drug safety and effectiveness studies are often challenged by various sources of bias. We undertook a systematic search of the published literature through September 2020 to evaluate the state of use and utility of negative controls to address bias in pharmacoepidemiologic studies. Two reviewers independently evaluated study eligibility and abstracted data. Our search identified 184 eligible studies for inclusion. Cohort studies (115, 63%) and administrative data (114, 62%) were, respectively, the most common study design and data type used. Most studies used negative control outcomes (91, 50%), and for most studies the target source of bias was unmeasured confounding (93, 51%). We identified 4 utility domains of negative controls: 1) bias detection (149, 81%), 2) bias correction (16, 9%), 3) P-value calibration (8, 4%), and 4) performance assessment of different methods used in drug safety studies (31, 17%). The most popular methodologies used were the 95% confidence interval and P-value calibration. In addition, we identified 2 reference sets with structured steps to check the causality assumption of the negative control. While negative controls are powerful tools in bias detection, we found many studies lacked checking the underlying assumptions. This article is part of a Special Collection on Pharmacoepidemiology.

Xenopus epidermal and endodermal epithelia as models for mucociliary epithelial evolution, disease, and metaplasia

The Xenopus embryonic epidermis is a powerful model to study mucociliary biology, development, and disease. Particularly, the Xenopus system is being used to elucidate signaling pathways, transcription factor functions, and morphogenetic mechanisms regulating cell fate specification, differentiation and cell function. Thereby, Xenopus research has provided significant insights into potential underlying molecular mechanisms for ciliopathies and chronic airway diseases. Recent studies have also established the embryonic epidermis as a model for mucociliary epithelial remodeling, multiciliated cell trans-differentiation, cilia loss, and mucus secretion. Additionally, the tadpole foregut epithelium is lined by a mucociliary epithelium, which shows remarkable features resembling mammalian airway epithelia, including its endodermal origin and a variable cell type composition along the proximal-distal axis. This review aims to summarize the advantages of the Xenopus epidermis for mucociliary epithelial biology and disease modeling. Furthermore, the potential of the foregut epithelium as novel mucociliary model system is being highlighted. Additional perspectives are presented on how to expand the range of diseases that can be modeled in the frog system, including proton pump inhibitor-associated pneumonia as well as metaplasia in epithelial cells of the airway and the gastroesophageal region.

Bias in pharmacoepidemiologic studies using secondary health care databases: a scoping review

BACKGROUND

The availability of clinical and therapeutic data drawn from medical records and administrative databases has entailed new opportunities for clinical and epidemiologic research. However, these databases present inherent limitations which may render them prone to new biases. We aimed to conduct a structured review of biases specific to observational clinical studies based on secondary databases, and to propose strategies for the mitigation of those biases.

METHODS

Scoping review of the scientific literature published during the period 2000-2018 through an automated search of MEDLINE, EMBASE and Web of Science, supplemented with manually cross-checking of reference lists. We included opinion essays, methodological reviews, analyses or simulation studies, as well as letters to the editor or retractions, the principal objective of which was to highlight the existence of some type of bias in pharmacoepidemiologic studies using secondary databases.

RESULTS

A total of 117 articles were included. An increasing trend in the number of publications concerning the potential limitations of secondary databases was observed over time and across medical research disciplines. Confounding was the most reported category of bias (63.2% of articles), followed by selection and measurement biases (47.0% and 46.2% respectively). Confounding by indication (32.5%), unmeasured/residual confounding (28.2%), outcome misclassification (28.2%) and "immortal time" bias (25.6%) were the subcategories most frequently mentioned.

CONCLUSIONS

Suboptimal use of secondary databases in pharmacoepidemiologic studies has introduced biases in the studies, which may have led to erroneous conclusions. Methods to mitigate biases are available and must be considered in the design, analysis and interpretation phases of studies using these data sources.

Hip fracture care in Manitoba, Canada and New York State, United States: an analysis of administrative data

BACKGROUND

Nearly 30 years ago, a series of studies showed increased hip fracture mortality in Manitoba compared to the United States, but these data have not been updated. Our objective was to compare the organization of hip fracture care and short-term outcomes in Manitoba and New York State using contemporary data.

METHODS

This was a retrospective cohort study of administrative data for all adults aged 50 years or more admitted to hospital with hip fracture between Jan. 1, 2011, and Oct. 31, 2013 in Manitoba and New York State. We compared the 2 jurisdictions with respect to: 1) the proportion of hospitals treating hip fracture and annual hip fracture volume, 2) hospital length of stay, 3) death and 4) hospital readmission. We used descriptive statistics, univariate methods and regression models to compare differences in care between jurisdictions.

RESULTS

We identified 2845 patients (mean age 82.2 yr, 2061 women [72.4%]) with hip fracture in Manitoba and 31 524 patients (mean age 81.9 yr, 22 973 women [72.9%]) with hip fracture in New York. A smaller proportion of hospitals in Manitoba than in New York treated hip fracture (7/30 [23%] v. 180/239 [75.3%]) (p < 0.001); the mean annual hospital hip fracture volume was higher in Manitoba (140.0) than in New York (68.9), but the difference did not reach statistical significance (p = 0.2). For patients with femoral neck fractures, the median hospital length of stay was longer in Manitoba than in New York (13 d v. 7 d). The rate of death within 7 days of admission was similar in Manitoba and New York (1.3% v. 2.0%, p = 0.07), although the rate of in-hospital death was higher in Manitoba (5.7% v. 3.5%, p < 0.001). Readmission within 30 days of discharge was less frequent in Manitoba than in New York (9.8% v. 12.0%, p = 0.02). Results were similar for patients with intertrochanteric fractures.

INTERPRETATION

Poor short-term outcomes for patients with hip fracture in Manitoba that were documented in the 1980s seem to have been eliminated. Our results should provide optimism that reengineering of clinical care can produce substantive improvements in quality.

Proton Pump Inhibitors and Infant Pneumonia/Other Lower Respiratory Tract Infections: National Nested Case-control Study

OBJECTIVE

The possible association between the use of proton pump inhibitors (PPIs) and community-acquired pneumonia (CAP) or another lower respiratory tract infection (LRTI) remains uncertain. We conducted a nested case-control study using routinely collected national health and drug dispensing data in New Zealand to examine the risk of CAP or another LRTI resulting in hospitalization or death in infants dispensed a PPI.

STUDY DESIGN

The cohort included 21,991 patients without a history of CAP or another LRTI who were born between 1 January 2005 and 31 December 2012 and were dispensed omeprazole, lansoprazole, or pantoprazole (the PPIs available in New Zealand during the study period) on at least one occasion during the first year of life. Cases had a first diagnosis after cohort entry (first PPI dispensing) of CAP (n = 65) validated by hospital discharge letter or death record, and chest radiography; or LRTI (including CAP) (n = 566) validated by hospital discharge letter or death record, with or without chest radiography. Up to 10 controls, matched by sex and date of birth, were randomly selected for each case. We conducted complete case analyses for the fully adjusted models.

RESULTS

In the adjusted analysis based on CAP cases and their controls, the matched odds ratio for current versus past use of PPIs was 0.88 (95% confidence interval 0.36-2.16). For all LRTI cases and their controls, the matched odds ratio was 1.13 (0.87-1.48).

CONCLUSION

In otherwise healthy community-dwelling infants, current use of a PPI does not appear to increase the risk of CAP or other LRTIs.

Do outpatient statins and ACEIs/ARBs have synergistic effects in reducing the risk of pneumonia? A population-based case-control study

Whether statins and an angiotensin-converting enzyme inhibitors (ACEIs) / angiotensin receptor blockors (ARBs) are associated with reduced risks of infection events is still inconclusive. This study aimed to explore the risk of hospitalization for pneumonia among patients who had received treatment with ACEIs/ARBs and/or statins using a population-based dataset. This study included 19,281 patients as cases who were hospitalized for pneumonia and 19,281 controls. We used a logistic regression to compute the odds ratio (OR) and 95% confidence interval (CI) for having previously used statins or an ACEI/ ARB between patients who were hospitalized for pneumonia treatment and controls. We found there were significant associations between hospitalization for pneumonia and statin-only users (p<0.001), ACEI/ARB-only users (p<0.001), and statin and ACEI/ARB users (p<0.001). The logistic regression analysis suggested that statin-only users (adjusted OR = 0.38, 95% CI = 0.34~0.43), ACEI/ARB-only users (adjusted OR = 0.86, 95% CI = 0.82~0.91), and statin and ACEI/ARB users (adjusted OR = 0.47, 95% CI = 0.44~0.50) were all less likely to be hospitalized for pneumonia treatment than were non-users. Furthermore, we found that statin-only users (adjusted OR = 0.44, 95% CI = 0.40~0.50) and statin and ACEI/ARB users (adjusted OR = 0.55, 95% CI = 0.52~0.58) were less likely to be hospitalized for pneumonia treatment compared to ACEI-only users. However, combined statin and ACEI/ARB users (adjusted OR = 1.24, 95% CI = 1.10~1.40) were more likely to have been hospitalized for pneumonia treatment compared to statin-only users. Although we found use of both statins and ACEI/ARB were significantly associated with a lower risk of pneumonia, the combination of the two medications did not provide additional protection against pneumonia risk.

Brief Report: Negative Controls to Detect Selection Bias and Measurement Bias in Epidemiologic Studies

Supplemental Digital Content is available in the text.

Biomedical laboratory experiments routinely use negative controls to identify possible sources of bias, but epidemiologic studies have infrequently used this type of control in their design or measurement approach. Recently, epidemiologists proposed the routine use of negative controls in observational studies and defined the structure of negative controls to detect bias due to unmeasured confounding. We extend this previous study and define the structure of negative controls to detect selection bias and measurement bias in both observational studies and randomized trials. We illustrate the strengths and limitations of negative controls in this context using examples from the epidemiologic literature. Given their demonstrated utility and broad generalizability, the routine use of prespecified negative controls will strengthen the evidence from epidemiologic studies.

Proton pump inhibitors therapy and risk of Clostridium difficile infection: Systematic review and meta-analysis

AIM

To perform a systematic review and meta-analysis on proton pump inhibitors (PPIs) therapy and the risk of Clostridium difficile infection (CDI).

METHODS

We conducted a systematic search of MEDLINE/PubMed and seven other databases through January 1990 to March 2017 for published studies that evaluated the association between PPIs and CDI. Adult case-control and cohort studies providing information on the association between PPI therapy and the development of CDI were included. Pooled odds ratios (ORs) estimates with 95% confidence intervals (CIs) were calculated using the random effect. Heterogeneity was assessed by I² test and Cochran’s Q statistic. Potential publication bias was evaluated via funnel plot, and quality of studies by the Newcastle-Otawa Quality Assessment Scale (NOS).

RESULTS

Fifty-six studies (40 case-control and 16 cohort) involving 356683 patients met the inclusion criteria and were analyzed. Both the overall pooled estimates and subgroup analyses showed increased risk for CDI despite substantial statistical heterogeneity among studies. Meta-analysis of all studies combined showed a significant association between PPI users and the risk of CDI (pooled OR = 1.99, CI: 1.73-2.30, P < 0.001) as compared with non-users. The association remained significant in subgroup analyses: by design-case-control (OR = 2.00, CI: 1.68-2.38, P < 0.0001), and cohort (OR = 1.98, CI: 1.51-2.59, P < 0.0001); adjusted (OR = 1.95, CI: 1.67-2.27, P < 0.0001) and unadjusted (OR = 2.02, CI: 1.41-2.91, P < 0.0001); unicenter (OR = 2.18, CI: 1.72-2.75, P < 0.0001) and multicenter (OR = 1.82, CI: 1.51-2.19, P < 0.0001); age ≥ 65 years (OR = 1.93, CI: 1.40-2.68, P < 0.0001) and < 65 years (OR = 2.06, CI: 1.11-3.81, P < 0.01). No significant differences were found in subgroup analyses (test for heterogeneity): P = 0.93 for case-control vs cohort, P = 0.85 for adjusted vs unadjusted, P = 0.24 for unicenter vs multicenter, P = 0.86 for age ≥ 65 years and < 65 years. There was significant heterogeneity across studies (I² = 85.4%, P < 0.001) as well as evidence of publication bias (funnel plot asymmetry test, P = 0.002).

CONCLUSION

This meta-analysis provides further evidence that PPI use is associated with an increased risk for development of CDI. Further high-quality, prospective studies are needed to assess whether this association is causal.

Cost Effectiveness of Gastroprotection with Proton Pump Inhibitors in Older Low-Dose Acetylsalicylic Acid Users in the Netherlands

Purpose

The present study aimed to assess the cost effectiveness of concomitant proton pump inhibitor (PPI) treatment in low-dose acetylsalicylic acid (LDASA) users at risk of upper gastrointestinal (UGI) adverse effects as compared with no PPI co-medication with attention to the age-dependent influence of PPI-induced adverse effects.

Methods

We used a Markov model to compare the strategy of PPI co-medication with no PPI co-medication in older LDASA users at risk of UGI adverse effects. As PPIs reduce the risk of UGI bleeding and dyspepsia, these risk factors were modelled together with PPI adverse effects for LDASA users 60–69, 70–79 (base case) and 80 years and older. Incremental cost-utility ratios (ICURs) were calculated as cost per quality-adjusted life-year (QALY) gained per age category. Furthermore, a budget impact analysis assessed the expected changes in expenditure of the Dutch healthcare system following the adoption of PPI co-treatment in all LDASA users potentially at risk of UGI adverse effects.

Results

PPI co-treatment of 70- to 79-year-old LDASA users, as compared with no PPI, resulted in incremental costs of €100.51 at incremental effects of 0.007 QALYs with an ICUR of €14,671/QALY. ICURs for 60- to 69-year-old LDASA users were €13,264/QALY and €64,121/QALY for patients 80 years and older. Initiation of PPI co-treatment for all Dutch LDASA users of 60 years and older at risk of UGI adverse effects but not prescribed a PPI (19%) would have cost €1,280,478 in the first year (year 2013 values).

Conclusions

PPI co-medication in LDASA users at risk of UGI adverse effects is generally cost effective. However, this strategy becomes less cost effective with higher age, particularly in patients aged 80 years and older, mainly due to the increased risks of PPI-induced adverse effects.

The Rotterdam Study: 2016 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over 1200 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.