Quality of prescribing predicts hospitalisation in octogenarians: life and living in advanced age: a cohort study in New Zealand (LiLACS NZ).

Background: Prescribing for older people is complex, and many studies have highlighted that appropriate prescribing in this cohort is not always achieved. However, the long-term effect of inappropriate prescribing on outcomes such as hospitalisation and mortality has not been demonstrated. The aim of this study was to determine the level of potentially inappropriate prescribing (PIP) for participants of the Life and Living in Advanced Age: A Cohort Study in New Zealand (LiLACS NZ) study at baseline and examine the association between PIP and hospitalisation and mortality at 12-months follow-up.

Methods: PIP was determined using STOPP/START. STOPP identified potentially inappropriate medicines (PIMs) prescribed, START identified potential prescribing omissions (PPOs). STOPP/START were applied to all LiLACS NZ study participants, a longitudinal study of ageing, which includes 421 Māori aged 80-90 years and 516 non-Māori aged 85 years. Participants' details (e.g. age, sex, living arrangements, socioeconomic status, physical functioning, medical conditions) were gathered by trained interviewers. Some participants completed a core questionnaire only, which did not include medications details. Medical conditions were established from a combination of self-report, review of hospital discharge and general practitioner records. Binary logistic regression, controlled for multiple potential confounders, was conducted to determine if either PIMs or PPOs were associated with hospital admissions and mortality (p < 0.05 was considered significant).

Results: Full data were obtained for 267 Māori and 404 non-Māori. The mean age for Māori was 82.3(±2.6) years, and 84.6(±0.53) years for non-Māori. 247 potentially inappropriate medicines were identified, affecting 24.3% Māori and 28.0% non-Māori. PIMs were not associated with 12-month mortality or hospitalisation for either cohort (p > 0.05; adjusted models). 590 potential prescribing omissions were identified, affecting 58.1% Māori and 49.0% non-Māori. PPOs were associated with hospitalisation (p = 0.001 for Māori), but were not associated with risk of mortality (p > 0.05) for either cohort within the 12-month follow-up (adjusted models).

Conclusion: PPOs were more common than PIMs and were associated with an increased risk of hospitalisation for Māori. This study highlights the importance of carefully considering all indicated medicines when deciding what to prescribe. Further follow-up is necessary to determine the long-term effects of PIP on mortality and hospitalisation.