Medication-related harm in New Zealand general practice: a retrospective records review

Background: The extent of medication-related harm in general practice is unknown.

Aim: To identify and describe all medication-related harm in electronic general practice records. The secondary aim was to investigate factors potentially associated with medication-related harm.

Design and setting: Retrospective cohort records review study in 44 randomly selected New Zealand general practices for the 3 years 2011-2013.

Method: Eight GPs reviewed 9076 randomly selected patient records. Medication-related harms were identified when the causal agent was prescribed in general practice. Harms were coded by type, preventability, and severity. The number and proportion of patients who experienced medication-related harm was calculated. Weighted logistic regression was used to identify factors associated with harm.

Results: In total, 976 of 9076 patients (10.8%) experienced 1762 medication-related harms over 3 years. After weighting, the incidence rate of all medication-related harms was 73.9 harms per 1000 patient-years, and the incidence of preventable, or potentially preventable, medication-related harms was 15.6 per 1000 patient-years. Most harms were minor (n = 1385/1762, 78.6%), but around one in five harms were moderate or severe (n = 373/1762, 21.2%); three patients died. Eighteen study patients were hospitalised; after weighting this correlates to a hospitalisation rate of 1.1 per 1000 patient-years. Increased age, number of consultations, and number of medications were associated with increased risk of medication-related harm. Cardiovascular medications, antineoplastic and immunomodulatory agents, and anticoagulants caused most harm by frequency and severity.

Conclusion: Medication-related harm in general practice is common. This study adds to the evidence about the risk posed by medication in the real world. Findings can be used to inform decision making in general practice.