Relationship between polypharmacy and underprescribing

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Polypharmacy is common among the elderly. • Underprescribing is also frequent. • Optimizing polypharmacy includes avoiding underprescription. WHAT THIS STUDY ADDS • The probability of underprescription increases with the number of drugs used. • Forty‐three % of patients who used five or more medicines are undertreated. • In undertreated patients a mean of 1.4 medicines were lacking. AIMS Underprescribing is increasingly recognized as an important problem. The aim of this study was to determine the relationship between polypharmacy and underprescribing. METHODS Treatment of current medical problems in geriatric patients was compared with general practitioner and national guidelines. Underprescription was defined as lack of an indicated drug, while no reason could be found for not prescribing it. Polypharmacy was defined as five or more drugs. RESULTS Polypharmacy was present in 61% of 150 patients. Underprescription was found in 47 (31%). Of patients with polypharmacy 42.9% were undertreated, in contrast to 13.5% of patients using four medicines or less (OR 4.8, 95% CI 2.0, 11.2). The estimated probability of underprescription increased significantly with the number of drugs. CONCLUSIONS We found a clear relationship between polypharmacy and underprescribing.