Intra-provincial variation of brief substance use withdrawal hospitalizations in Ontario, Canada: a cross-sectional study

Objective — In Ontario, substance use disorders are the top reason for mental health and addictions-related hospitalizations, many of which are related to substance withdrawal. Our objective was to identify briefer withdrawal-related hospitalizations that are potentially manageable in medically supported community-based settings, assess the degree of intra-provincial variation for these types of admissions, and examine the health care utilization of these patients.

Methods — We conducted a population-based, cross-sectional study using linked health administrative data for Ontario residents hospitalized with alcohol- or opioid-use withdrawal between January 1, 2019 to December 31, 2021. Brief withdrawal admissions (BWAs) were defined as hospitalizations with a stay of 0–4 days and without intensive care. We calculated BWA rates per 100,000 person-years (PY), overall and for health regions within the province. Log-binomial regression models were used to examine differences in health care utilization in the year following a BWA compared with the year prior to admission.

Results — There were 12,544 BWAs in Ontario during our study period (28.6 admissions per 100,000 PY) with a greater than 7-fold difference (p < 0.001) between the provincial health regions with the highest (North West region, 149.5 per 100,000 PY) and lowest (Central region, 20.8 per 100,000 PY) rate. In the year following a BWA, 30% of patients required hospital admission and 50% had an emergency department visit for substance use, which represented a significant increase of 63% (Relative Rate (RR) = 1.63; 95% Confidence Interval (95% CI) 1.55–1.71, P-value <0.001) and 11% (RR = 1.11; 95% CI 1.08–1.14, P-value <0.001), compared with the year prior to admission, respectively.

Conclusions — Understanding the variation in BWAs, and the significant health care use following such events, is vital in supporting provincial efforts to improve withdrawal management. Future research should examine if providing more resources to community-based withdrawal services to manage BWAs results in improved patient outcomes and reduced acute care capacity/costs.