Model selection in linear mixed model analysis in a RCT of medications for opioid treatment

Music City Center 

A key step in the analysis of longitudinal changes of polysubstance cravings in MOUD treatment using linear mixed model (LMM) is to choose a suitable covariance structure. Data was selected from the National Drug Abuse Treatment Clinical Trials Network protocol-0051. Opioid-dependent participants were randomly assigned to receive BUP-NX (n=287) or XR-NTX (n=283). Measures of opiate, alcohol, stimulant, and nicotine craving were collected at baseline and every 4 weeks for 8 months. Both AIC and BIC statistics revealed that the unstructured (UN) covariance structure is the best from ten common covariance structures for these four craving measures. Using a UN model in the LMM, all four craving measures declined rapidly from baseline. Baseline depression and alcohol, amphetamine, and cocaine use disorders were associated with an increased risk of alcohol, stimulant and nicotine cravings. In conclusion, the UN covariance structure is the best in the LMM, while screening for depression and multiple substances may help clinicians identify patients at a higher vulnerability for opioid relapse secondary to possible increased cravings of substances.

Opioid use disorders

Clinical trial

Linear mixed model

Model selection

Substance use

Craving 

Mental Health Statistics Section