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Drug complications in outpatients


OBJECTIVE: Outpatient drug complications have not been well studied. We sought to assess the incidence and characteristics of outpatient drug complications, identify their clinical and nonclinical correlates, and evaluate their impact on patient satisfaction.

DESIGN: Retrospective chart reviews and patient surveys.

SETTING: Eleven Boston-area ambulatory clinics.

PATIENTS: We randomly selected 2,248 outpatients, 20 to 75 years old.

MEASUREMENTS AND MAIN RESULTS: Among 2,248 patients reporting prescription drug use, 394 (18%) reported a drug complication. In contrast, chart review revealed an adverse drug event in only 64 patients (3%). In univariate analyses, significant correlates of patient-reported drug complications were number of medical problems, number of medications, renal disease, failure to explain side effects before treatment, lower medication compliance, and primary language other than English or Spanish. In multivariate analysis, independent correlates were number of medical problems (odds ratio [OR] 1.17; 95% confidence interval [95% CI] 1.05 to 1.30), failure to explain side effects (OR 1.65; 95% CI, 1.16 to 2.35), and primary language other than English or Spanish (OR 1.40; 95% CI, 1.01 to 1.95). Patient satisfaction was lower among patients who reported drug complications (P < .0001). In addition, 48% of those reporting drug complications sought medical attention and 49% experienced worry or discomfort. On chart review, 3 (5%) of the patients with an adverse drug event required hospitalization and 8 (13%) had a documented previous reaction to the causative drug.

CONCLUSIONS: Drug complications in the ambulatory setting were common, although most were not documented in the medical record. These complications increased use of the medical system and correlated with dissatisfaction with care. Our results indicate a need for better communication about potential side effects of medications, especially for patients with multiple medical problems.

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  1. Cypress BW. Drug Utilization in Office Visits to Primary Care Physicians: National Ambulatory Medical Care Survey, 1980. Department of Health and Human Services publication (PHS) 82-1250. Washington, DC: Public Health Service; 1982.

    Google Scholar 

  2. Bates DW, Cullen D, Laird N, et al. Incidence of adverse drug events and potential adverse drug events: implications for prevention. JAMA. 1995;274:29–34.

    PubMed  Article  CAS  Google Scholar 

  3. Classen DC, Pestotnik SL, Evans RS, Lloyd JF, Burke JP. Adverse drug events in hospitalized patients. Excess length of stay, extra costs, and attributable mortality. JAMA. 1997;277:301–6.

    PubMed  Article  CAS  Google Scholar 

  4. Leape LL, Brennan TA, Laird NM, et al. The nature of adverse events in hospitalized patients: results from the Harvard Medical Practice Study II. N Engl J Med. 1991;324:377–84.

    PubMed  CAS  Article  Google Scholar 

  5. Bates DW, Spell N, Cullen DJ, et al. The costs of adverse drug events in hospitalized patients. JAMA. 1997;227:307–11.

    Article  Google Scholar 

  6. Leape LL, Bates DW, Cullen DJ, et al. Systems analysis of adverse drug events. JAMA. 1995;274:35–43.

    PubMed  Article  CAS  Google Scholar 

  7. Lazarou J, Pomeranz BH, Corey PN. Incidence of adverse drug reactions in hospitalized patients: a meta-analysis of prospective studies. JAMA. 1998;279:1200–5.

    PubMed  Article  CAS  Google Scholar 

  8. Bates DW. Drugs and adverse drug reactions. How worried should we be? JAMA. 1998;279(15):1216–7.

    PubMed  Article  CAS  Google Scholar 

  9. Phillips DP, Christenfeld N, Glynn LM. Increase in US medication-error deaths between 1983 and 1993. Lancet. 1998;351:643–4.

    PubMed  Article  CAS  Google Scholar 

  10. Hutchinson TA, Flegel KM, Kramer MS, Leduc DG, Kong HPK. Frequency, severity and risk factors for adverse drug reactions in adult outpatients: a prospective study. J Clin Epidemiol. 1986;39:533–42.

    CAS  Google Scholar 

  11. Hanlon JT, Schmader KE, Koronkowski MJ, et al. Adverse drug events in high risk older outpatients. J Am Geriatr Soc. 1997;45:945–8.

    PubMed  CAS  Google Scholar 

  12. O’Neil AC, Petersen LA, Cook EF, Bates DW, Lee TH, Brennan TA. Physician reporting compared with medical-record review to identify adverse medical events. Ann Intern Med. 1993;119:370–6.

    PubMed  CAS  Google Scholar 

  13. Jones JK. Assessing potential risk of drugs: the elusive target. Ann Intern Med. 1992;117:691–2. Editorial.

    PubMed  CAS  Google Scholar 

  14. Tarlov AR, Ware JE Jr, Greenfield S, Nelson EC, Perrin E, Zubkoff M. The Medical Outcomes Study: an application of methods for monitoring the results of medical care. JAMA. 1989;262:925–30.

    PubMed  Article  CAS  Google Scholar 

  15. Chrischilles EA, Segar ET, Wallace RB. Self-reported adverse drug reactions and related resource use: a study of community-dwelling persons 65 years of age and older. Ann Intern Med. 1992;117:634–40.

    PubMed  CAS  Google Scholar 

  16. Physicians’ Desk Reference. 52nd ed. Montvale, NJ: Medical Economics Data Production Co; 1998.

  17. Naranjo CA, Busto U, Sellers EM, et al. A method for estimating the probability of adverse drug reactions. Clin Pharmacol Ther. 1981;30:239–45.

    PubMed  CAS  Article  Google Scholar 

  18. Jha AK, Kuperman GJ, Teich JM, et al. Identifying adverse drug events: development of a computer-based monitor and comparison to chart review and stimulated voluntary report. J Am Med Inform Assoc. 1998;5(3):305–14.

    PubMed  CAS  Google Scholar 

  19. Classen DC, Pestotnik SL, Evans RS, Burke JP. Computerized surveillance of adverse drug events in hospital patients. JAMA. 1991;266:2847–51.

    PubMed  Article  CAS  Google Scholar 

  20. Bates DW, O’Neil AC, Boyle D, et al. Potential identifiability and preventability of adverse events using information systems. J Am Med Inform Assoc. 1994;1:404–11.

    PubMed  CAS  Google Scholar 

  21. Honigman B, Bates DW, Light P. Computerized data mining for adverse drug events in an outpatient setting [abstract]. Proc AMIA Symp. 1998;1018.

  22. Gonzales R, Steiner JF, Sande MA. Antibiotic prescribing for adults with colds, upper respiratory tract infections, and bronchitis by ambulatory care physicians. JAMA. 1997;278(11):901–4.

    PubMed  Article  CAS  Google Scholar 

  23. Fuchsberg A. Medical malpractice — catch 29 or catch 22. Trial Lawyers Q. 1978;12:9–15.

    Google Scholar 

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Correspondence to David W. Bates MD, MSc.

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This work was supported by a grant from the Harvard Risk Management Foundation.

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Gandhi, T.K., Burstin, H.R., Cook, E.F. et al. Drug complications in outpatients. J GEN INTERN MED 15, 149–154 (2000).

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Key words

  • adverse drug events
  • ambulatory care
  • patient satisfaction
  • quality of care
  • drug complication