The relationship between variations in antipsychotic prescribing across nursing homes and short-term mortality: quality of care implications

Background — High rates of antipsychotic drug prescribing in nursing homes can signal poor quality processes, but also raise concerns about drug safety due to the mortality risk of this therapy. Determining the extent to which variations in antipsychotic use are a symptom of facility-level quality problems as compared with a drug safety issue is important for selecting the correct interventions to effect change.

Objective — To determine whether nursing homes with higher rates of antipsychotic dispensing had higher rates of short-term mortality among their residents.

Methods — This population-based study examined 60,105 older adults newly admitted to nursing homes in Ontario between April 1, 2000 and March 31, 2004. Using adjusted Cox proportional hazard models, we explored the relationship between facility-level dispensing rates and mortality, controlling for resident characteristics. Facilities were grouped into quintiles according to mean antipsychotic rate. All-cause mortality at 30 and 120 days after admission was stratified by recent hospital discharge and analyzed by quintile.

Results — Average antipsychotic dispensing ranged from 11.6% in the lowest quintile to 30.0% in the highest. Among residents with no recent hospitalization, all-cause mortality at 30 days was 2.5% in the lowest compared with 3.3% in the highest quintile (adjusted hazard ratio: 1.28, confidence interval: 1.06–1.56) and at 120 days was 9.3% compared with 11.7% (adjusted hazard ratio: 1.25, confidence interval: 1.13–1.39).

Conclusion — Residents were at increased risk of death simply by being admitted to a facility with a higher intensity of antipsychotic drug use, despite similar clinical characteristics at admission.