Abstract Background Patients with opioid use disorder are at a higher cardiovascular risk due to the effect of opioids on the cardiovascular system. Cardiac conduction abnormalities, electrical activity impairment, cardiac arrhythmias, and ventricular hypertrophy are reported in the opioid population. Objective This study aimed to assess the prevalence and factors associated with ECG abnormalities among adults with opioid use disorder attending the Itega addiction center for methadone-assisted therapy (MAT). Methodology A cross-sectional analytical study was conducted among adult outpatients attending the Itega addiction center in Dodoma. A calculated sample size of 321was attained through a convenience sampling approach. A standard 12-lead ECG was recorded for each participant and interpreted by two independent cardiologists. Univariate and multivariable logistic regression was computed to determine the factors associated with ECG abnormalities. Under adjusted analysis, a p-value of less than 0.05 was considered significant for factors associated with ECG abnormalities after controlling for all the variables with a minimum p-value of 0.2 at univariate analysis. Results The majority of 308 (95.95%) of the participants were males, 197 (61.37%) had attained primary education level, and the mean age of the participants was 35.44 ± 6.54 years. The overall prevalence for any ECG abnormalities in this study was 26.47%, with Sinus bradycardia 59(18.4%) being the most observed ECG abnormality, followed by QTc prolongation 27(8.41%). A month's increase in the duration on MAT and being a female were significantly associated with lower odds of ECG abnormalities (AOR =0.85, 95% CI =0.74-0.96 p =0.014) and (AOR = 0.05, 95% CI = 0.01-0.59, p = 0.017) respectively.  Conclusion The high prevalence of ECG Abnormalities implies high cardiovascular risk among a population with opioid use disorder. Given that majority of the ECG abnormalities are treatable, integrating cardiovascular care in the opioid addiction clinic would be beneficial for this population.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethical approval was obtained from the University of Dodoma with reference number "NO.UDOM/RP/68/Vo1.IV/10". Permission to conduct the study was obtained from Itega addiction Centre.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

Data will be shared as supplementary file under request