Sources of heterogeneity in case–control studies on associations between statins, ACE-inhibitors, and proton pump inhibitors and risk of pneumonia (original) (raw)
Abstract
The heterogeneity in case–control studies on the associations between community-acquired pneumonia (CAP) and ACE-inhibitors (ACEi), statins, and proton pump inhibitors (PPI) hampers translation to clinical practice. Our objective is to explore sources of this heterogeneity by applying a common protocol in different data settings. We conducted ten case–control studies using data from five different health care databases. Databases varied on type of patients (hospitalised vs. GP), level of case validity, and mode of exposure ascertainment (prescription or dispensing based). Identified CAP patients and controls were matched on age, gender, and calendar year. Conditional logistic regression was used to calculate odds ratios (OR) for the associations between the drugs of interest and CAP. Associations were adjusted by a common set of potential confounders. Data of 38,742 cases and 118,019 controls were studied. Comparable patterns of variation between case–control studies were observed for ACEi, statins and PPI use and pneumonia risk with adjusted ORs varying from 1.04 to 1.49, 0.82 to 1.50 and 1.16 to 2.71, respectively. Overall, higher ORs were found for hospitalised CAP patients matched to population controls versus GP CAP patients matched to population controls. Prevalence of drug exposure was higher in dispensing data versus prescription data. We show that case–control selection and methods of exposure ascertainment induce bias that cannot be adjusted for and to a considerable extent explain the heterogeneity in results obtained in case–control studies on statins, ACEi and PPIs and CAP. The common protocol approach helps to better understand sources of variation in observational studies.
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References
- Myles PR, Hubbard RB, McKeever TM, Pogson Z, Smith CJ, Gibson JE. Risk of community-acquired pneumonia and the use of statins, ace inhibitors and gastric acid suppressants: a population-based case–control study. Pharmacoepidemiol Drug Saf. 2009;18(4):269–75. doi:10.1002/pds.1715.
Article PubMed CAS Google Scholar - van de Garde EM, Endeman H, Deneer VH, et al. Angiotensin-converting enzyme insertion/deletion polymorphism and risk and outcome of pneumonia. Chest. 2008;133(1):220–5.
Article PubMed Google Scholar - Israili ZH, Hall WD. Cough and Angioneurotic Edema Associated with Angiotensin-Converting Enzyme Inhibitor Therapy: A Review of the Literature and Pathophysiology. Ann Intern Med. 1992;117(3):234–42. doi:10.7326/0003-4819-117-3-234.
Article PubMed CAS Google Scholar - Caldeira D, Alarcao J, Vaz-Carneiro A, Costa J. Risk of pneumonia associated with use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers: systematic review and meta-analysis. BMJ. 2012;345(jul11 1):e4260-e. doi:10.1136/bmj.e4260.
- Douglas I, Evans S, Smeeth L. Effect of statin treatment on short term mortality after pneumonia episode: cohort study. BMJ. 2011;342:d1642. doi:10.1136/bmj.d1642.
Article PubMed PubMed Central Google Scholar - Chopra V, Flanders SA. Statins and pneumonia. BMJ. 2011;342:d1907. doi:10.1136/bmj.d1907.
Article PubMed Google Scholar - Eom CS, Jeon CY, Lim JW, Cho EG, Park SM, Lee KS. Use of acid-suppressive drugs and risk of pneumonia: a systematic review and meta-analysis. CMAJ. 2011;183(3):310–9. doi:10.1503/cmaj.092129.
Article PubMed PubMed Central Google Scholar - Lipchik RJ. Review: ACE inhibitors reduce risk for pneumonia. Ann Intern Med. 2012;157(10):JC5-2. doi:10.7326/0003-4819-157-10-201211200-02002.
Article PubMed Google Scholar - Danaei G, Tavakkoli M, Hernan MA. Bias in observational studies of prevalent users: lessons for comparative effectiveness research from a meta-analysis of statins. Am J Epidemiol. 2012;175(4):250–62. doi:10.1093/aje/kwr301.
Article PubMed PubMed Central Google Scholar - Rothman KJ, Greenland S. Causation and causal inference in epidemiology. Am J Public Health. 2005;95(S1):S144–50. doi:10.2105/AJPH.2004.059204.
Article PubMed Google Scholar - Stirbu-Wagner I, Dorsman SA, Visscher S et al. Landelijk Informatienetwerk Huisartsenzorg. Feiten en cijfers over huisartsenzorg in Netherlands. 2010. http://www.nivel.nl/representativiteit-van-linh. Accessed Sept 2012.
- Klungel OH, Rietveld MC, de Groot MCH, et al. The Mondriaan Project: the Dutch health care landscape as a population laboratory. Value in Health. 2009;12(7):A392. doi:10.1016/s1098-3015(10)74933-0.
Article Google Scholar - Remmelts HHF, Spoorenberg SMC, Oosterheert JJ, Bos WJ, de Groot MCH, van de Garde EMW. The role of vitamin D supplementation in the risk of developing pneumonia: three independent case–control studies. Thorax. 2013;68(11):990–6. doi:10.1136/thoraxjnl-2013-203623.
Article PubMed Google Scholar - Grobbee DE, Hoes AW, Verheij TJ, Schrijvers AJ, van Ameijden EJ, Numans ME. The Utrecht Health Project: optimization of routine healthcare data for research. Eur J Epidemiol. 2005;20(3):285–7.
Article PubMed Google Scholar - Fine MJ, Singer DE, Hanusa BH, Lave JR, Kapoor WN. Validation of a pneumonia prognostic index using the MedisGroups Comparative Hospital database. Am J Med. 1993;94(2):153–9.
Article PubMed CAS Google Scholar - Meijvis SC, Hardeman H, Remmelts HH, et al. Dexamethasone and length of hospital stay in patients with community-acquired pneumonia: a randomised, double-blind, placebo-controlled trial. Lancet. 2011;377(9782):2023–30. doi:10.1016/S0140-6736(11)60607-7.
Article PubMed CAS Google Scholar - van de Garde EM, Endeman H, van Hemert RN, et al. Prior outpatient antibiotic use as predictor for microbial aetiology of community-acquired pneumonia: hospital-based study. Eur J Clin Pharmacol. 2008;64(4):405–10. doi:10.1007/s00228-007-0407-0.
Article PubMed PubMed Central Google Scholar - Meijvis SC, Cornips MC, Voorn GP, et al. Microbial evaluation of proton-pump inhibitors and the risk of pneumonia. Eur Respir J. 2011;38(5):1165–72. doi:10.1183/09031936.00020811.
Article PubMed CAS Google Scholar - Almirall J, Bolíbar I, Serra-Prat M, et al. Inhaled drugs as risk factors for community-acquired pneumonia. Eur Respir J. 2010;36(5):1080–7. doi:10.1183/09031936.00022909.
Article PubMed CAS Google Scholar - Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ. 2003;327(7414):557–60. doi:10.1136/bmj.327.7414.557.
Article PubMed PubMed Central Google Scholar - van Gageldonk-Lafeber AB, Bogaerts MA, Verheij RA, van der Sande MA. Time trends in primary-care morbidity, hospitalization and mortality due to pneumonia. Epidemiol Infect. 2009;137(10):1472–8. doi:10.1017/S0950268809002258.
Article PubMed Google Scholar - Schouten JA, Prins JM, Bonten MJ, et al. Revised SWAB guidelines for antimicrobial therapy of community-acquired pneumonia. Neth J Med. 2005;63(8):323–35.
PubMed CAS Google Scholar - Dublin S, Walker RL, Jackson ML, Nelson JC, Weiss NS, Jackson LA. Angiotensin-converting enzyme inhibitor use and pneumonia risk in community-dwelling older adults: results from a population-based case–control study. Pharmacoepidemiol Drug Saf. 2012;21(11):1173–82. doi:10.1002/pds.3340.
Article PubMed CAS PubMed Central Google Scholar - van de Garde EMW, Deneer VH, Souverein PC, van den Bosch JM, Leufkens HGM. Validation of community-acquired pneumonia: high positive predictive value for ICD-9 codes. Pharmacoepidemiol Drug Saf. 2008;17:S248. doi:10.1002/pds.
Article Google Scholar - Rafailidis PI, Matthaiou DK, Varbobitis I, Falagas ME. Use of ACE inhibitors and risk of community-acquired pneumonia: a review. Eur J Clin Pharmacol. 2008;64(6):565–73. doi:10.1007/s00228-008-0467-9.
Article PubMed CAS Google Scholar - Hu Z, Jin X, Kang Y, et al. Angiotensin-converting enzyme insertion/deletion polymorphism associated with acute respiratory distress syndrome among caucasians. J Int Med Res. 2010;38(2):415–22. doi:10.1177/147323001003800204.
Article PubMed CAS Google Scholar - Majumdar SR, McAlister FA, Eurich DT, Padwal RS, Marrie TJ. Statins and outcomes in patients admitted to hospital with community acquired pneumonia: population based prospective cohort study. BMJ. 2006;333(7576):999. doi:10.1136/bmj.38992.565972.7C.
Article PubMed PubMed Central Google Scholar - Lipsitch M, Tchetgen Tchetgen E, Cohen T. Negative controls: a tool for detecting confounding and bias in observational studies. Epidemiology. 2010;21(3):383–8. doi:10.1097/EDE.0b013e3181d61eeb.
Article PubMed PubMed Central Google Scholar - McCandless LC. Statin use and fracture risk: can we quantify the healthy-user effect? Epidemiology. 2013;24(5):743–52. doi:10.1097/EDE.0b013e31829eef0a.
Article PubMed Google Scholar - Bavry AA, Bhatt DL. Interpreting observational studies—look before you leap. J Clin Epidemiol. 2006;59(8):763–4. doi:10.1016/j.jclinepi.2005.12.015.
Article PubMed Google Scholar - Smeeth L, Douglas I, Hall AJ, Hubbard R, Evans S. Effect of statins on a wide range of health outcomes: a cohort study validated by comparison with randomized trials. Br J Clin Pharmacol. 2009;67(1):99–109. doi:10.1111/j.1365-2125.2008.03308.x.
Article PubMed PubMed Central Google Scholar - Glynn RJ, Schneeweiss S, Wang PS, Levin R, Avorn J. Selective prescribing led to overestimation of the benefits of lipid-lowering drugs. J Clin Epidemiol. 2006;59(8):819–28. doi:10.1016/j.jclinepi.2005.12.012.
Article PubMed Google Scholar
Acknowledgments
The authors thank Jan Vandenbroucke for his valuable discussions on methodology and interpretation of the analyses. This work was funded and performed within the framework of the Dutch Top Institute Pharma project T6-101-1 Mondriaan, The Dutch healthcare landscape as a ‘population laboratory’ (www.tipharma.com). We would like to thank the staff of all databases for their help in the data extraction.
Conflict of interest
Mark C. H. de Groot: The University of Utrecht has received funding from Top Institute Pharma to pay part of my salary. This public private partnership (funding: 50 % Government, 25 % Academia, 25 % pharmaceutical industry) supports project T6-101-1 Mondriaan, The Dutch healthcare landscape as a ‘population laboratory’ (www.tipharma.com). My employer received unrestricted support from the Innovative Medicine Initiative Joint Undertake (IMI-PROTECT: www.imi.europa.eu) under Grant Agreement No. 115004, resources of which are composed of financial contribution from the European Union’s Seventh Framework Programme (FP7/2007-2013) and EFPIA companies’ in kind contribution. Olaf H. Klungel received unrestricted research support from IMI-PROTECT and IMI-EU2P for development of educational presentations. Hubert G. M. Leufkens has no personal funding to declare. Liset van Dijk has received unrestricted grants from Bristol Myers-Squibb, Astra Zeneca and Pfizer. Diederick E. Grobbee has nothing to declare. Ewoudt M. W. van de Garde has received unrestricted funding from the Netherlands Organisation for Health Research and Development (ZonMW) and GlaxoSmithKline that is not related to the present project.
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Authors and Affiliations
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, PO Box 80082, 3508 TB, Utrecht, The Netherlands
Mark C. H. de Groot, Olaf H. Klungel, Hubert G. M. Leufkens, Liset van Dijk & Ewoudt M. W. van de Garde - Nivel, Netherlands Institute for Healthcare Research, Utrecht, The Netherlands
Liset van Dijk - Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
Diederick E. Grobbee - Department of Clinical Pharmacy, St. Antonius Hospital, Nieuwegein, The Netherlands
Ewoudt M. W. van de Garde
Authors
- Mark C. H. de Groot
- Olaf H. Klungel
- Hubert G. M. Leufkens
- Liset van Dijk
- Diederick E. Grobbee
- Ewoudt M. W. van de Garde
Corresponding author
Correspondence toMark C. H. de Groot.
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de Groot, M.C.H., Klungel, O.H., Leufkens, H.G.M. et al. Sources of heterogeneity in case–control studies on associations between statins, ACE-inhibitors, and proton pump inhibitors and risk of pneumonia.Eur J Epidemiol 29, 767–775 (2014). https://doi.org/10.1007/s10654-014-9941-0
- Received: 07 April 2014
- Accepted: 22 July 2014
- Published: 26 August 2014
- Issue date: October 2014
- DOI: https://doi.org/10.1007/s10654-014-9941-0