Prevalence, nature and predictors of omitted medication doses in mental health hospitals: A multi-centre study

Limited evidence concerning the burden and predictors of omitted medication doses within mental health hospitals could severely limit improvement efforts in this specialist setting. This study aimed to determine the prevalence, nature and predictors of omitted medication doses affecting hospital inpatients in two English National Health Service (NHS) mental health trusts.

Over 6 data collection days trained pharmacy teams screened inpatient prescription charts for scheduled and omitted medication doses within 27 adult and elderly wards across 9 psychiatric hospitals. Data were collected for inpatients admitted up to two weeks prior to each data collection day. Omitted doses were classified as 'time critical' and 'preventable' based on established criteria. Omitted dose frequencies were presented with 95% confidence intervals (CI). Multilevel logistic regression analyses determined the predictors of omitted dose occurrence, with omission risks presented as adjusted odds ratios (OR) with 95% CI.

18,664 scheduled medication doses were screened for 444 inpatients and 2,717 omissions were identified, resulting in a rate of 14.6% (95% CI 14.1-15.1). The rate of 'time critical' omitted doses was 19.3% (95% CI 16.3-22.6%). 'Preventable' omitted doses comprised one third of all omissions (34.5%, 930/2694). Logistic regression analysis revealed that medicines affecting the central nervous system were 55% less likely to be omitted compared to all other medication classes (9.9% vs. 18.8%, OR 0.45 (0.40-0.52)) and that scheduled doses administered using non-oral routes were more likely to be omitted compared the oral route (inhaled OR 3.47 (2.64-4.57), topical 2.71 (2.11-3.46), 'other' 2.15 (1.19-3.90)). 'Preventable' dose omissions were more than twice as likely to occur for 'time critical' medications than non-time critical medications (50.4% vs. 33.8%, OR 2.24 (1.22-4.11)).

Omitted medication doses occur commonly in mental health hospitals with 'preventable' omissions a key contributor to this burden. Important targets for remedial intervention have been identified.