Medication omission rates in New Zealand residential aged care homes: a national description

BACKGROUND: A medication omission is an event where a prescribed medication is not taken before the next scheduled dose. Medication omissions are typically classed as errors within Residential Aged Care (RAC) homes, as they have the potential to lead to harm if poorly managed, but may also stem from good clinical decision-making. This study aimed to quantify the incidence, prevalence, and types of medication omissions in RAC homes on a national scale, using a New Zealand-based sample. METHODS: We conducted retrospective pharmacoepidemiology of de-identified medication administration e-records from December 1st 2016 to December 31st 2017. Four tiers of de-identified data were collected: RAC home level data (ownership, levels of care), care staff level data (competency level/role), resident data (gender, age, level of care), and medication related data (omissions, categories of omissions, recorded reasons for omission). Data were analysed using SPSS version 24 and Microsoft Excel. RESULTS: A total of 11, 015 residents from 374 RAC homes had active medication charts; 8020 resided in care over the entire sample timeframe. A mean rate of 3.59 medication doses were omitted per 100 (±7.43) dispensed doses/resident. Seventy-three percent of residents had at least one dose omission. The most common omission category used was ‘not-administered’ (49.9%), followed by ‘refused’ (34.6%). The relationship between ownership type and mean rate of omission was significant (p = 0.002), corporate operated RAC homes had a slightly higher mean (3.73 versus 3.33), with greater variation. The most commonly omitted medications were Analgesics and Laxatives. Forty-eight percent of all dose omissions were recorded without a comment justifying the omission. CONCLUSIONS: This unique study is the first to report rate of medication omissions per RAC resident over a one-year timeframe. Although the proportion of medications omitted reported in this study is less than previously reported by hospital-based studies, there is a significant relationship between a resident’s level of care, RAC home ownership types, and the rate of omission.