Opioid withdrawal symptoms, frequency, and pain characteristics as correlates of health risk among people who inject drugs.

Objective: Opioid withdrawal symptoms are widely understood to contribute to health risk but have rarely been measured in community samples of opioid using people who inject drugs (PWID).

Methods: Using targeted sampling methods, 814 PWID who reported regular opioid use (at least 12 uses in the last 30 days) were recruited and interviewed about demographics, drug use, health risk, and withdrawal symptoms, frequency, and pain. Multivariable regression models were developed to examine factors associated with any opioid withdrawal, withdrawal frequency, pain severity, and two important health risks (receptive syringe sharing and non-fatal overdose).

Results: Opioid withdrawal symptoms were reported by 85 % of participants in the last 6 months, with 29 % reporting at least monthly withdrawal symptoms and 35 % reporting at least weekly withdrawal symptoms. Very or extremely painful symptoms were reported by 57 %. In separate models, we found any opioid withdrawal (adjusted odds ratio [AOR] = 2.75, 95 % confidence interval [CI] = 1.52, 5.00) and weekly or more opioid withdrawal frequency (AOR = 1.94; 95 % CI = 1.26, 3.00) (as compared to less than monthly) to be independently associated with receptive syringe sharing while controlling for confounders. Any opioid withdrawal (AOR = 1.71; 95 % CI = 1.04, 2.81) was independently associated with nonfatal overdose while controlling for confounders. In a separate model, weekly or more withdrawal frequency (AOR = 1.69; 95 % CI = 1.12, 2.55) and extreme or very painful withdrawal symptoms (AOR = 1.53; 95 % CI = 1.08, 2.16) were associated with nonfatal overdose as well.

Conclusions: Withdrawal symptoms among PWID increase health risk. Treatment of withdrawal symptoms is urgently needed and should include buprenorphine dispensing.