Theme: Epidemiology & Public Health Research Year: 2018
Unstably housed people who inject drugs (PWID) face an array of negative outcomes, including
higher risks of unsafe injecting and HCV acquisition compared to their stably housed counterparts.
However, the interaction between drug injecting and housing stability over time remains poorly
understood. This study aimed to investigate correlations between injecting frequency and housing
stability trajectories evolving concomitantly over 12 months.
At three-month intervals, HCV RNA-negative PWID enrolled between 03/2011 and 06/2016 in a
cohort study were tested for HCV and completed an interviewer-administered questionnaire. At
each visit, participants reported the number of injecting days (0-30 days) and unstable housing
(hotel/motel room, rooming/boarding house, shelter, or street) for each of the past three months.
Participants were included if observations were available for ≥6 out of 12 months. Group-based
dual trajectory modeling was performed using censored normal and logistic models for injecting
frequency and housing stability trajectories, respectively.
386 participants (mean age 40, 82% male) contributed 3,725 observations. Five injecting
frequency trajectories were identified: sporadic (estimated probability of group membership,
26%), infrequent (34%), increasing (15%), decreasing (11%), and frequent (13%). Three housing
stability trajectories were identified: sustained (53%), declining (20%), and improving (27%). The
probability of improving housing stability was higher among PWID who injected frequently (22%),
sporadically (20%), or infrequently (14%) compared to those with increasing (8%) or decreasing
injecting (11%). Moreover, the probability of a decline in housing stability was lower among PWID
who injected frequently (23%) compared to those with other injecting trajectories (≥29%).
PWID with stable injecting trajectories (frequent, sporadic, and infrequent injecting) were more
likely to improve housing stability over time compared to those with varying trajectories (increasing
or decreasing injecting). The association between frequent injecting and improving housing
stability is novel, yet a better understanding of the underlying mechanisms is needed.
Disclosure of Interest Statement:
This work was supported by the Canadian Institutes of Health Research (CIHR) and the Fonds
de recherche du Québec – Santé (FRQS). None of the authors has commercial relationships that
might pose a conflict of interest in connection with this work. EF is supported through a CIHR