Number of medications or number of diseases: what influences underprescribing?

PURPOSE: An increasing number of older adults suffer from multimorbidity and receive multiple medications. Despite that, underprescribing of potentially beneficial medications is widespread in this population. Our aim was to examine influence of polypharmacy and multimorbidity on the presence of prescribing omissions (PO) in general practice attenders.

METHODS: We conducted a cross-sectional study of older adults attending general practices in Slovenia who were regularly prescribed at least one medication. Patients' data was entered into a computer application evaluating the presence of START (Screening Tool to Alert doctors to Right Treatment) criteria for PO. Demographic data, CIRS-G (Cumulative Illness Rating Scale for geriatric patients) questionnaire, number of medications, and healthcare utilization data were also collected. We defined polypharmacy as five or more concurrent medications.

RESULTS: Five hundred three patients were enrolled, 258 (56.7%) female. The average age was 74.9 and average value of CIRS-G index 1.48 (± 0.6). Patients took on average 5.6 medications and 216 (42.9%) patients had at least one PO according to START criteria. In bivariate analysis, there was a significant association between age, number of medications, polypharmacy and CIRS-G index measures, and presence of PO. In multivariate analysis, only age and number of affected CIRS-G categories significantly predicted PO (p < 0.05).

CONCLUSIONS: Older patients with more affected CIRS-G categories were at higher risk for PO. Polypharmacy was not an independent risk factor for the presence of PO. A possible reason is that in multimorbid older people, physicians and patients set individual priorities to treatment instead of treating all diseases and conditions.