The prevalence of QT prolongation in a population of patients with substance use disorders

Methadone-associated QT interval prolongation in patients undergoing maintenance therapy in an urban opioid treatment program

STUDY OBJECTIVE

Methadone is associated with QT interval prolongation and torsades de pointes. The objective of this study was to (a) determine the incidence of QT interval prolongation among patients on maintenance methadone therapy in an urban opioid treatment program (OTP), (b) compare characteristics of patients who developed methadone-associated QT prolongation with those who did not develop QT prolongation, and (c) investigate the relationship between QT interval prolongation and stereospecific serum methadone and metabolite [2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP)] concentrations.

DESIGN

Prospective study.

SETTING

Urban opioid treatment program (OTP).

PATIENTS

n = 93 patients on maintenance methadone therapy in an urban OTP.

INTERVENTION

Patients underwent a 12-lead electrocardiogram (ECG) prior to initiating methadone and again during steady-state maintenance methadone therapy. In a subset (n = 43), blood was obtained to determine serum (S)- and (R)-methadone and (S)- and (R)-EDDP concentrations, which were compared in patients who developed Bazett's-corrected QT (QTc) prolongation [≥470 ms (men) or ≥480 ms (women) and/or ≥60 ms lengthening from pretreatment value] with those who did not have QTc prolongation.

MEASUREMENTS AND MAIN RESULTS

Mean [± standard deviation (SD)] age was 36 ± 12 years; 73% were female, and 74% were white. QTc prolongation occurred in 14 (15.1%) patients. Patients who developed QTc prolongation were older (41 ± 13 vs. 35 ± 9 years, p = 0.03) and had a longer pre-methadone QTc compared with those who did not have QTc prolongation (429 ± 11 vs. 420 ± 20 ms, respectively, p = 0.02). Serum (S)-methadone concentrations were higher in patients with QTc prolongation compared to patients without prolongation (199 ± 81 vs. 128 ± 68 ng/ml, respectively, p = 0.01), whereas the difference in serum (R)-methadone concentrations between the groups did not reach significance (189 ± 68 vs. 125 ± 60 ng/ml, respectively, p = 0.08). Serum (R)-methadone concentrations correlated with QTc intervals [R²  = 0.15 (95% confidence interval (CI) 0.11-0.62, p = 0.0009)]. The correlation between serum (S)-methadone concentrations and QTc did not reach significance [R²  = 0.08 (95% CI -0.01 to 0.54, p = 0.06)]. Serum (S)-and (R)-EDDP concentrations were not significantly different between the groups and did not significantly correlate with QTc intervals.

CONCLUSIONS

Approximately 15% of patients taking maintenance methadone therapy developed QT interval prolongation. Both serum (S)- and (R)-methadone concentrations, but not (S)- or (R)-EDDP, contribute to methadone-associated QT prolongation.

Prevalence of ECG abnormalities and risk factors for QTc interval prolongation in hospitalized psychiatric patients

BACKGROUND

Psychiatric patients are at risk of cardiovascular diseases, and many psychotropic drugs can prolong QTc interval. Requirements for electrocardiogram (ECG) monitoring have been set up in our psychiatric university hospital. The objective of this study was to determine the proportion of adult patients who had an ECG during their hospitalization, the prevalence of ECG abnormalities, the evolution of the QTc after admission, and the risk factors for QTc prolongation.

METHODS

Retrospective analysis of ECGs and clinical data of all patients with a complete hospitalization in 2015. Assessment of the influence of covariates on QTc using linear mixed-effects models.

RESULTS

At least one ECG (n = 600) was performed during 37.6% of the stays (n = 1198) and in 45.5% of the patients (n = 871). Among the patients with an ECG, 17.9% had significant ECG abnormalities, including 7.6% with a prolonged QTc. QTc measured at admission and during hospitalization did not change significantly (n = 46, 419.4 ± 29.7 ms, 417.2 ± 27.6 ms, p = 0.71). In the multivariate model (292 patients, 357 ECGs), the covariates significantly associated with the QTc were gender (+15.9 ms if female, p < 0.0001), age (+0.4 ms/year, p = 0.0001), triglyceride levels (+5.7 ms/mmol/l, p = 0.005), and drugs with known risk of torsades de pointes (+6.2 ms if ⩾1 drug, p = 0.028).

CONCLUSIONS

The prevalence of hospitalized psychiatric patients with an abnormal ECG indicates that ECGs should be performed systematically in this population. Prescription of psychotropic drugs should be done cautiously, particularly in patients with QTc prolongation risk factors.

Opioid Drug Use and Acute Cardiac Events Among Pregnant Women in the United States

BACKGROUND

Cardiovascular disease remains a leading cause of pregnancy-associated deaths in the United States. The extent to which increasing opioid use among pregnant women contributes to fatal cardiovascular events is unknown. We examined trends in opioid use among pregnant women over the previous decade and the association between changes in temporal trends in opioid drug use and the incidence of acute cardiac events among mothers.

METHODS

In this retrospective analysis of the Healthcare and Cost Utilization Project, we used a 2-stage stratified cluster sampling of all inpatient hospital discharges from nonfederal hospitals from January 1, 2002 through December 31, 2014. The study population comprised pregnant women aged 13-49 years and related hospitalizations, including delivery. The primary exposure of interest was opioid use during pregnancy. The primary outcome was the occurrence of acute myocardial infarction or cardiac arrest during pregnancy or childbirth.

RESULTS

Among the estimated 57.4 million pregnancy-related inpatient hospitalizations, 511,469 (approximately 1%) had documented use of opioids, cocaine, and/or amphetamines. There was a 300% increase in the use of opioids during pregnancy over the study period, whereas cocaine consumption significantly decreased and that of amphetamine remained stable. Over the 13-year period, the rise in opioid use paralleled a 50% increase in the incidence of acute cardiac events among mothers.

CONCLUSION

Over the previous decade opioid use during pregnancy increased significantly, in parallel with the rise in the incidence of acute cardiac events in pregnancy and childbirth. An effective national policy is needed to address this emerging public health challenge.

QT interval prolongation in opioid agonist treatment: analysis of continuous 12-lead electrocardiogram recordings

AIMS

Methadone is a widely used opioid agonist treatment associated with QT prolongation and torsades de pointes. We investigated the QT interval in patients treated with methadone or buprenorphine using continuous 12-lead Holter recordings.

METHODS

We prospectively made 24-h Holter recordings in patients prescribed methadone or buprenorphine, compared to controls. After their normal dose a continuous 12-lead Holter recorder was attached for 24 h. Digital electrocardiograms were extracted hourly from the Holter recordings. The QT interval was measured automatically (H-scribe software, Mortara Pty Ltd) and checked manually. The QT interval was plotted against heart rate (HR) on the QT nomogram to determine abnormality. Demographics, dosing, medical history and laboratory investigations were recorded.

RESULTS

There were 58 patients (19 methadone, 20 buprenorphine and 19 control); median age 35 years (20-56 years); 33 males. Baseline characteristics were similar. Median dose of methadone was 110 mg day-1 (70-170 mg day-1 ) and buprenorphine was 16 mg day-1 (12-32 mg day-1 ). Seven participants had abnormal QT intervals. There was a significant difference in the proportion of prescribed methadone with abnormal QT intervals, 7/19 (37%; 95% confidence interval: 17-61%), compared to controls 0/19 (0%; 95% confidence interval: 0-21%; P = 0.008), but no difference between buprenorphine and controls (0/20). QT vs. HR plots showed patients prescribed methadone had higher QT-HR pairs over 24 h compared to controls. There was no difference in dose for patients prescribed methadone with abnormal QT intervals and those without.

CONCLUSIONS

Methadone is associated with prolonged QT intervals, but there was no association with dose. Buprenorphine did not prolong the QT interval. Twenty four-hour Holter recordings using the QT nomogram is a feasible method to assess the QT interval in patients prescribed methadone.