Clinically important drug-disease interactions and their prevalence in older adults.
BACKGROUND
Older adults may have decreased homeostatic reserve, have multiple chronic diseases, and take multiple medications. Therefore, they are at risk for adverse outcomes after receiving a drug that exacerbates a chronic disease.


OBJECTIVE
The aims of this study were to compile a list of clinically important drug-disease interactions in older adults, obtain the consensus of a multidisciplinary panel of geriatric health care professionals on these interactions, and determine the prevalence of these interactions in a sample of outpatients.


METHODS
This analysis included a 2-round modified Delphi survey and cross-sectional study. Possible drug-disease interactions in patients aged > or =65 years were identified through a search of the English-language literature indexed on MEDLINE and International Pharmaceutical Abstracts (1966-July 2004) using terms that included drug-disease interaction, medication errors, and inappropriate prescribing. Nine health care professionals with expertise in geriatrics (2 geriatricians, 7 geriatric clinical pharmacist specialists) were selected based on specialty training and continuing clinical work in geriatrics, academic appointments, and geographic location. The panel rated the importance of the potential drug-disease interactions using a 5-point Likert scale (from 1 = definitely not serious to 5 = definitely serious). Consensus on a drug-disease interaction was defined as a lower bound of the 95% CI > or =4.0. The prevalence of drug-disease interactions was determined by applying the consensus criteria to a convenience sample of frail older veterans at hospital discharge who were enrolled in a health services intervention trial.


RESULTS
The panel reached consensus on 28 individual drug-disease interactions involving 14 diseases or conditions. Overall, 205 (15.3%) of the 1340 veterans in the sample had > or =1 drug-disease interaction. The 2 most common drug-disease interactions were use of first-generation calcium channel blockers in patients with congestive heart failure and use of aspirin in patients with peptic ulcer disease (both, 3.7%).


CONCLUSIONS
A survey of multidisciplinary geriatric health care professionals resulted in a concise consensus list of clinically important drug-disease interactions in older adults. Further research is needed to examine the impact of these drug-disease interactions on health outcomes and their applicability as national measures for the prevention of drug-related problems.
Lindblad
Catherine I
CI
Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Minneapolis, Minnesota, USA. Electronic address: lindb047@umn.edu.
Hanlon
Joseph T
JT
Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Center for Health Equity Research and Promotion, Geriatric Research, Education, and Clinical Center, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh Pennsylvania, USA; Department of Pharmacy and Therapeutics, School of Pharmacy, University of Pittsburgh Pittsburgh, Pennsylvania, USA.
Gross
Cynthia R
CR
Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota.
Sloane
Richard J
RJ
Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, USA.
Pieper
Carl F
CF
Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, USA; Department of Biostatistics and Bioin formatics, Duke University Medical Center, Durham, North Carolina, USA.
Hajjar
Emily R
ER
Philadelphia College of Pharmacy, University of the Sciences in Philadelphia, Philadelphia, Pennsylvania, USA.
Ruby
Christine M
CM
Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Pharmacy and Therapeutics, School of Pharmacy, University of Pittsburgh Pittsburgh, Pennsylvania, USA.
Schmader
Kenneth E
KE
Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, North Carolina, USA; Division of Geriatric Medicine, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Durham, North Carolina, USA.
Multidisciplinary Consensus Panel
D000368:Aged; D001241:Aspirin / Q000009:adverse effects; D002121:Calcium Channel Blockers / Q000009:adverse effects; D002908:Chronic Disease; D064420:Drug-Related Side Effects and Adverse Reactions; D016330:Frail Elderly; D015577:Geriatric Assessment; D006801:Humans; D008508:Medication Errors / Q000706:statistics & numerical data*; D015995:Prevalence; D014728:Veterans
D002121:Calcium Channel Blockers; D001241:Aspirin