Relationship between number of drugs and duration of hospital stay in older patients with neuromuscular diseases.

AIM: Older patients are considered to be at high risk for developing adverse drug reactions (ADR), because they commonly receive multidrug therapy despite changes in pharmacokinetic function with age. In the present study, we assessed the relationship between the number of prescribed drugs and the incidence of ADR or the time to discharge in older patients with neuromuscular disease.

METHODS: A retrospective study was carried out among 135 older patients (aged ≥65 years) who were admitted to the neurology ward from October 2007 through December 2011. Drugs that possess a high risk for initiation of grade ≥2 ADR were determined using logistic regression analysis.

RESULTS: A total of 38 patients (28.1%) experienced grade ≥2 ADR. Multivariate logistic regression analysis showed that corticosteroids, antibiotics, enteric nutrients and insulin were significant risks for grade ≥2 ADR. Notably, the time to discharge extended as the grade of ADR increased, with mean values of 24.4 days for grade 0, 38.3 days for grade 1, 47.5 days for grade 2 and 73.1 days for grade 3-4 events. Furthermore, the number of high-risk drugs for grade ≥2 ADR correlated well with the incidence of grade ≥2 events (R = 0.964, P = 0.008), as well as with the time to discharge (R = 0.473, P < 0.001).

CONCLUSIONS: Older patients receiving multidrug therapy using corticosteroids, antibiotics, enteric nutrients, or insulin were at high risk for grade ≥2 ADR and prolongation of hospital stay. Geriatr Gerontol Int 2018; 18: 1018-1024.