In reply:

Abstract

Editor's note: The above letter was sent to the authors of the original article; their reply follows. In Reply: We appreciate the interest of Adhiyaman et al. in our study. The letter points to some of the limitations in performing population-based studies. Our findings were derived from the analysis of secondary data. As such, our objectives were pursued within the limits of data collected for other purposes. Additionally, the data for this study was collected over a period of 2 years, 1994–96, and so drug information would be based on what was used at the time of interview. Finally, as in most cross-sectional studies, the duration and chronicity of drug use cannot be ascertained with complete accuracy. We agree with the assertion of Adhiyaman et al. that prescribing for older people is fraught with difficulties because multiple pathology, which allows for the prescription of drugs with contraindications or potential for interaction, is more often the rule. We were therefore prudent in interpreting the results of our findings by stating that we found substantial exposure to presumptively inappropriate use of drugs in this very old population (Discussion, page 281, paragraph 3, and Conclusion, page 282, paragraph 1). The contention of Adhiyaman et al. as to whether we were justified in calling all potential drug-drug and drug-disease interactions inappropriate suggests that they overlooked our comments on this matter. As a second point, Adhiyaman et al. noted recent evidence to support the use of beta-blockers in patients with congestive heart failure. We also pointed this out in our discussion on page 282, paragraph 5. As to the absence of antidepressants, amiodarone, and warfarin in drug-drug or drug-disease interactions, no mention of these was made because no such combinations occurred in our study. Given the difference in analyzing data in a population-based study compared with an investigation of subjects from a hospital setting, we believe that we have the same objective as the letter's author. There is a need for careful assessment when prescribing drugs in older patients to avoid unnecessary risks for adverse drug events.