Efficient sampling approaches to address confounding in database studies

Abstract

Administrative and other population-based databases are widely used in pharmacoepidemiology to study the unintended effects of medications. They allow investigators to study large case series, and they document prescription medication exposure without having to contact individuals or medical charts, or rely on human recall. However, such databases often lack information on potentially important confounding variables. This review describes some of the sampling approaches and accompanying data-analysis methods that can be used to assess, and deal efficiently with, such confounding.

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References

Miettinen OS The need for randomization in the study of intended effects. Statistics in Medicine 1983 ; 2: 267-71.

Vandenbroucke JP The history of confounding. Sozial- und Präventivmedizin/Social and Preventive Medicine 2004; 47: 216-24.

Breslow NE , Day NE Statistical methods in cancer research. Volume I - The analysis of case-control studies. IARC Scientific Publication number 32. 1980.

Miettinen OS Components of the crude risk ratio. American Journal of Epidemiology 1972; 96: 168-72.

Cornfield J. , Haenszel W. , Hammond E. , Lilienfeld A. , Shimkin M. , Wynder E. Smoking and lung cancer: Recent evidence and a discussion of some questions. Journal of the National Cancer Institute 1959; 22: 173-203.

Woolf B. On estimating the relation between blood group and disease. Annals of Human Genetics 1955; 11: 251-3.

Greenland S. (Editor). Evolution of Epidemiologic Ideas: Annotated Readings on Concepts and Methods. Epidemiology Resources Inc. Ch. 4. 1987.

Miettinen OS (1976). Estimability and estimation in case-referent studies. American Journal of Epidemiology 103: 226-35.

Miettinen OS

Epidemiology: quo vadis?

European Journal of Epidemiology 2004; 19: 713-8.

10.

Miettinen OS Important concepts in epidemiology. Chapter 2 in Teaching Epidemiology: A Guide for Teachers in Epidemiology, Public Health and Clinical Medicine , 3rd edn, Olsen , Saracci , Trichopoulos (eds.) 2008 to appear.

11.

Breslow NE , Day NE Statistical Methods in Cancer Research: Volume II: The Design and Analysis of Cohort Studies, IARC Scientific Publication , No 82. 1987.

12.

Mantel N. and Haenszel W. Statistical aspects of the analysis of data from retrospective studies of disease. Journal of the National Cancer Institute 1959; 22: 719-48.

13.

Breslow NE Elementary methods of cohort analysis. Int J Epidemiol 1984; 13:112-5.

14.

Robins J. , Breslow N. , Greenland S. Estimators of the Mantel-Haenszel variance consistent in both sparse data and large-strata limiting models. Biometrics 1986; 42: 311-23.

15.

Rothman KJ Epidemiology: an introduction Oxford University Press, New York, 2002.

16.

Smith PG , Day NE The design of case-control studies: the influence of confounding and interaction effects. International Journal of Epidemiology 1984; 13: 356-65.

17.

Smith PG , Day NE : Matching and confounding in the design and analysis of epidemiological case-control studies. Perspectives in Medical Statistics, J.F. Bithell , R. Coppi , eds. Academic Press, London , 1987: 39-64.

18.

Helms M. , Vastrup P. , Gerner-Smidt P. , Mlbak K. Short and long term mortality associated with foodborne bacterial gastrointestinal infections: registry based study. BMJ 2003 ; 15; 326(7385): 357.

19.

Walker AM Efficient assessment of confounder effects in matched follow-up studies . Applied Statistics 1982; 31: 293-7.

20.

Ayas NT , Barger LK , Cade BE , Hashimoto DM , Rosner B. , Cronin JW , Speizer FE , Czeisler CA Extended work duration and the risk of self-reported percutaneous injuries in interns. JAMA 2006; 296: 1055-62.

21.

Maclure M. The Case-Crossover Design: A Method for Studying Transient Effects on the Risk of Acute Events. American Journal of Epidemiology 1991; 133: 144-53.

22.

Haddon W. , Valien P. , McCarroll JR , Umberger CJ A controlled investigation of the characteristics of adult pedestrians fatally injured by motor vehicles in Manhattan. Journal of Chronic Diseases 1961; 14: 655-78.

23.

Schneeweiss S. , Patrick AR , Stürmer T. , Brookhart MA , Avorn J. , Maclure M. , Rothman KJ , Glynn RJ Increasing levels of restriction in pharma-coepidemiologic database studies of elderly and comparison with randomized trial results. Medical Care 2007; 45: S131-42.

24.

Greenland S. Multiple-bias modeling for analysis of observational data. Journal of the Royal Statistical Society A 2005; 168: 267-306.

25.

Schneeweiss S. Sensitivity analysis and external adjustment for unmeasured confounders in epidemiologic database studies of therapeutics . Pharmacoepidemiology and Drug Safety 2006 ; 15: 291-303.

26.

Stürmer T. , Glynn RJ , Rothman KJ , Avorn J. , Schneeweiss S. Adjustments for unmeasured confounders in pharmacoepidemiologic database studies using external information. Medical Care 2007 ; 45: S158-65.

27.

Schneeweiss S. , Glynn RJ , Tsai EH , Avorn J. , Solomon DH Adjusting for unmeasured confounders in pharmacoepidemiologic claims data using external information: the example of COX2 inhibitors and myocardial infarction. Epidemiology 2005; 16: 17-24.

28.

Thürigen D. , Spiegelman D. , Blettner M. , Heuer C. , Brenner H. Measurement error correction using validation data: a review of methods and their applicability in case-control studies . Statistical Methods in Medical Research 2000; 9: 447-74.

29.

Stürmer T. , Schneeweiss S. , Avorn J. , Glynn RJ Adjusting effect estimates for unmeasured confounding with validation data using propensity score calibration. American Journal of Epidemiology 2005; 162: 279-89.

30.

Opatrny L. , Delaney JAC , Suissa S. Gastrointestinal haemorrhage risks of selective serotonin receptor antagonist therapy: a new look. British Journal of Clinical Pharmacology DOI:10.1111/j.1365-2125.2008.03154.x

31.

Ray, WA and Griffin, MR Use of Medicaid data for pharmacoepidemiology . American Journal of Epidemiology 1989; 129: 837-49.

32.

Ray WA , Griffin MR , Malcolm E. Cyclic antidepressants and the risk of hip fracture. Archives of Intern Medicine 1991; 151: 754-56.

33.

Suissa S. , Edwardes MD Adjusted odds ratios for case-control studies with missing confounder data in controls. Epidemiology 1997; 8: 275-80.

34.

Hanley JA Two-phase case-control studies: a personal account. Australasian Epidemiologist 1998; 5: 12-3.

35.

Sharpe CR , Collet JP , Belzile E. , Hanley JA , Boivin JF The effects of tricyclic antidepressants on breast cancer risk. Br J Cancer 2002; 86: 92-7.

36.

Sharpe CR , Collet JP , McNutt M. , Belzile E. , Boivin JF , Hanley JA Nested case-control study of the effects of non-steroidal anti-inflammatory drugs on breast cancer risk and stage. Br J Cancer 2000; 83: 112-120.

37.

White JE A two stage design for the study of the relationship between a rare exposure and a rare disease. American Journal of Epidemiology 1982; 115: 119-28.

38.

Walker AM Anamorphic analysis: sampling and estimation for covariate effects when both exposure and disease are known. Biometrics 1982; 38: 1025-32.

39.

Breslow NE , Cain KC Logistic regression for two stage case-control data. Biometrika 1988; 75: 11-20.

40.

Cain KC , Breslow NE Logistic regression analysis and efficient design for two-stage studies . American Journal of Epidemiology 1988; 128: 1198-206.

41.

Lumley T. Analysis of Complex Survey Samples. Journal of Statistical Software 2004; 9: 1-19.

42.

Kleinbaum DG , Kupper LL , Morgenstern H. Epidemiologic research : principles and quantitative methods. Van Nostrand Reinhold, New York, 1982.

43.

Schaubel D. , Hanley J. , Collet JP , Bolvin JF , Sharpe C. , Morrison HI , Mao Y. Two-stage sampling for etiologic studies: sample size and power. Am J Epidemiol 1997 ; 146: 450-8.

44.

Collet JP , Schaubel D. , Hanley J. , Sharpe C. , Boivin JF Controlling confounding when studying large pharmacoepidemiologic databases: a case study of the two-stage sampling design. Epidemiology 1998; 9(3): 309-15.

45.

Hanley JA , Csizmadi I. , Collet JP Two-stage case-control studies: precision of parameter estimates and considerations in selecting sample size. American Journal of Epidemiology 2005; 162: 1225-34.

46.

Schill W. , Wild P. Minmax designs for planning the second phase in a two-phase case-control study . Statistics in Medicine 2006; 25: 1646-59.

47.

Schill W. Wild P. Pigeot I.

A planning tool for two-phase case-control studies

Computer Methods and Programs in Biomedicine 2007; 88: 175-81.

48.

Edwardes MD Sample size requirements for case-control study designs. BMC Medical Research Methodology 2001; 1:11doi:10.1186/1471-2288-1-11

49.

Breslow NE Case-control study, two-phase. In Armitage P , Colton T , eds. Encyclopedia of Biostatistics, 2nd Edition. John Wiley & Sons, Chichester, West Sussex, England; Hoboken, NJ, 2005.

50.

Chatterjee N. , Chen YH A semiparametric pseudo-score method for analysis of two-phase studies with continuous phase-I covariates. Lifetime Data Analysis 2007; 13: 607-622. Epub 2007 Nov 14.

51.

Eng PM , Seeger JD , Loughlin J. , Clifford CR , Mentor S. , Walker AM Supplementary data collection with case-cohort analysis to address potential confounding in a cohort study of thromboembolism in oral contraceptive initiators matched on claims-based propensity scores. Pharmacoepidemiology and Drug Safety 2008 ; 17: 297-305.

52.

Breslow NE Using the whole cohort in the analysis of case-control and case-cohort data . Under review.

53.

Langholz B. , Clayton D. Sampling strategies in nested case-control studies. Environmental Health Perspectives 1994; 102(Suppl 8): 47-51.

54.

Langholtz B. , Borgan O. Counter-matching: A stratified nested case-control sampling method. Biometrika 1995; 82 69-79.

55.

Cologne JB , Sharp GB , Neriishi K. , Verkasalo PK , Land CE , Nakachi K. Improving the efficiency of nested case-control studies of interaction by selecting controls using counter matching on exposure. Int. J. Epidemiology 2004; 33: 485-92.

56.

Wacholder S. , Rothman N. , Caporaso N. Population Stratification in Epidemiologic Studies of Common Genetic Variants and Cancer: Quantification of Bias Journal of the National Cancer Institute 2000; 92: 1151-8.

57.

Ritz B. , Wilhelm M. , Hoggatt KJ , Ghosh GKC. Ambient air pollution and preterm birth in the environment and pregnancy outcomes study at the University of California, Los Angeles American Journal of Epidemiology 2007; 166: 1045-52.

58.

Blais L. , Beauchesne MF , Rey E. , Malo JL , Forget A. Use of inhaled corticosteroids during the first trimester of pregnancy and the risk of congenital malformations among women with asthma. Thorax 2007; 62: 320-28.

59.

Haselkorn T. , Whittemore AS , Udaltsova N. , Friedman GD Short-term chloral hydrate administration and cancer in humans. Drug Safety 2006; 29: 67-77.