The Relationship Between Polypharmacy and Hospital-stay Duration: A Retrospective Study.

Background There have been very few studies on the association of polypharmacy with clinical course. In this paper, we seek to evaluate the relationship between polypharmacy and hospitalization period. Methods We retrospectively analyzed 322 patients hospitalized from February to September 2017, after excluding short-term and orthopedic cases. Patients with polypharmacy were defined as those who were prescribed more than five drugs at the time of admission. The primary endpoint for all subjects regardless of polypharmacy was the hospitalization period. Using Mann-Whitney U test results, we compared the average number of hospital days between patients with and without polypharmacy. Secondary endpoints were hospitalization period with and without polypharmacy for each disease type. Results The hospitalization period was significantly extended for patients with polypharmacy as compared to those without (31.6 vs. 23.2 days, p: 0.002). Those with an infection had significantly longer hospitalization than those without polypharmacy (27.6 vs. 18.1 days, p: 0.007). Malignancy, heart disease, and cerebrovascular disease did not have a significant effect on hospitalization regardless of polypharmacy. Conclusion Polypharmacy is related to an extended hospitalization period and is found to occur more frequently in patients hospitalized for an infection.