Original researchLooking Beyond Polypharmacy: Quantification of Medication Regimen Complexity in the Elderly
Introduction
Interest in the elderly and the amount of medications that they take has increased as they take >30% of all prescription medications in the United States and other developed countries.1, 2 Despite the fact that the number of drugs taken daily increases with age,3 age-related comorbidities, not age per se, carry a high risk of polypharmacy.4 Polypharmacy among the elderly, due to its inappropriate effect of under- and overprescribing, has been associated with poor adherence,1, 5, 6, 7 higher risk of adverse events,5, 8 higher health-care costs,5, 9 increased hospitalization,10, 11 and mortality.5, 12
A simple medication count is the most commonly used measurement of regimen complexity. However, when assessing medication regimens, the clinician should evaluate not only the number of drugs taken on a daily basis, but also the number of daily doses, frequency, and special instructions for use. Many studies revealed the negative effect of medical regimen complexity based on only 1 of the features of medication complexity, on adherence to specific medications,13, 14, 15 and health care expenditures.16 However, when evaluating the impact of medication regimens on outcomes, it is advantageous to quantify all of the various attributes of the medication regimens not considered by a simple medication count. An unpublished tool, the Medication Complexity Index,17 has been used by some researchers in specific populations18, 19 or certain diseases.20 However, its failure to confirm reasonable reliability with complex regimens and reveal any significant correlation with outcomes such as medication adherence,18 resulted in the development of the Medication Regimen Complexity Index (MRCI).21
The index was tested on medication regimens of patients with moderate to severe chronic obstructive pulmonary disease and was found to be reliable and valid for quantifying drug regimen complexity. It was subsequently translated into and validated in Portuguese and German.22, 23 The MRCI has been used to determine the association between drug prescription and quality of life in primary care.24 It has also been used to test medication self-management transition intervention for heart failure in older patients25 but without previous validation in hospitalized elderly patients.
To the best of our knowledge, no previous study has examined the relationship between medication regimen complexity assessed by the MRCI and medication adherence and medication modifications among discharged older patients.
The primary objective of our study was to test the convergent, discriminant, and predictive validity of the MRCI in older hospitalized patients with varying functional and cognitive levels. The secondary objective was to compare its discriminant and predictive validities to those of the number of medications.
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Study Design
This cohort study took place in the Acute Geriatric Ward, Beilinson Hospital, Rabin Medical Center, Petach Tikvah, Israel. The study was divided into 2 stages: prospective, with patient interviews and follow-up, and retrospective, reviewing the hospital files of patients who had participated in the prospective stage. In the prospective stage, patients' medication regimen continuity and adherence after hospital discharge were investigated and the results published elsewhere.26 All patients ≥65
Results
A total of 212 patients were enrolled in the study. Baseline characteristics of the study population are summarized in Table I. Mean age was 81.1 (7.3) years (range, 66–103 years). On admission, patients' mean number of chronic diseases was 6.3 (2.6) (range, 1–15) with a mean score of 9.2 (3.1) (range, 2–18) on the CIRS-G. Mean hospital length of stay was 10.7 (6.3) days (range, 2–39 years). Five patients died during their hospital stay.
Medication treatment characteristics of the patients at
Discussion
Our study validated the use of the MRCI for quantifying the complexity of a medication regimen among hospitalized elderly patients. The MRCI score on discharge was inversely correlated with adherence to discharge medication, but not with postdischarge medication modifications.
Good correlation was found between the MRCI score and the number of medications. However, it is important to note that the number of medications contributes to regimen complexity but does not constitute complexity per se.17
Conclusions
The MRCI showed satisfactory validity with applicability to clinical research and practice. There is good evidence confirming the benefit of its use for classifying regimen complexity over a simple medication count. We believe that the MRCI is a valuable tool for quantifying medication regimen complexity in clinical and epidemiological studies. However, the additional time, effort, and professional training needed for its calculation may decrease its use and its popularity. More prospective and
Conflicts of Interest
The authors have indicated that they have no conflicts of interest regarding the content of this article.
Acknowledgments
The authors thank Phyllis Curchack Kornspan for editorial services. All authors contributed equally to the manuscript.
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