Determining adherence to therapeutic regimens in patients with chronic illness: comment on the article by Waimann et Al

Low estimated glomerular filtration rate is an independent risk factor for higher hydroxychloroquine concentration

BACKGROUND

The aim of this study was to analyze the relationship of the estimated glomerular filtration rate (eGFR) to hydroxychloroquine (HCQ) blood concentrations in systemic lupus erythematosus (SLE) patients.

METHOD

Patients with SLE who had been taking HCQ for more than 12 months were recruited. All subjects gave written informed consent. Various clinical characteristics and laboratory values were examined. The blood concentration of HCQ was measured by high-performance liquid chromatography, and the relationship of eGFR to HCQ blood concentration was mainly investigated.

RESULT

In total, 115 patients with SLE receiving long-term HCQ therapy were included in the study. The median concentration of HCQ was 1096 ng/ml (range 116-8240 ng/ml). The eGFR was strongly associated with blood concentration of HCQ (P = 0.011, P < 0.05), when adjusted for age, sex, body mass index (BMI), weight-adjusted dose, prednisone use and immunosuppressive drug use. No statistically significant association were found between age, duration, BMI, weight-adjusted HCQ dose, corticosteroid use, immunosuppressant use and blood concentrations of HCQ.

CONCLUSION

We provided novel evidence that impaired renal function influenced the blood concentration of HCQ. Patients with low eGFR need to adjust the HCQ dosage according to the monitoring results of HCQ blood concentrations.

Clinical Significance of Monitoring Hydroxychloroquine Levels in Patients With Systemic Lupus Erythematosus: A Systematic Review and Meta-Analysis

OBJECTIVE

Despite the pivotal role that hydroxychloroquine (HCQ) plays in treating systemic lupus erythematosus (SLE), less than 50% of patients take HCQ as prescribed. Measurement of HCQ blood levels can help clinicians distinguish nonadherence versus lack of efficacy of HCQ. Our objective was to systematically review publications and perform a meta-analysis to examine the correlation between HCQ levels and 1) nonadherence and 2) Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, in SLE.

METHODS

A comprehensive search was performed. We included observational and interventional studies that measured HCQ levels and assessed adherence or SLEDAI scores in adults with SLE. Forest plots compared pooled estimates of correlations between HCQ levels and reported nonadherence or SLEDAI scores.

RESULTS

Among 604 studies screened, 17 were reviewed. We found 3-times higher odds of reported nonadherence in patients with low HCQ levels (odds ratio 2.95 [95% confidence interval (95% CI) 1.63, 5.35], P < 0.001). The mean SLEDAI score was 3.14 points higher in groups with below-threshold HCQ levels on a priori analysis (δ = 3.14 [95% CI -0.05, 6.23], P = 0.053), and 1.4 points higher in groups with HCQ levels of <500 ng/ml (δ = 1.42 [95% CI 0.07, 2.76], P = 0.039). Among 1,223 patients, those with HCQ levels ≥750 ng/ml had a 58% lower risk of active disease, and their SLEDAI score was 3.2 points lower.

CONCLUSION

We found a strong association between low HCQ levels and reported nonadherence. Our results suggest that HCQ levels of ≥750 ng/ml might be a potential therapeutic target.

Changing antimalarial agents after inefficacy or intolerance in patients with cutaneous lupus erythematosus: A multicenter observational study

BACKGROUND

Changing from one antimalarial (AM) agent to another is often recommended in cutaneous lupus erythematosus (CLE) when the first AM agent is ineffective or poorly tolerated.

OBJECTIVE

To evaluate the effect on cutaneous response of a switch from hydroxychloroquine to chloroquine, or the reverse, after failure of the first AM agent.

METHODS

We conducted a retrospective observational study between 1997 and September 2015. The overall cutaneous response rate and reasons for failure of the switch were assessed for up to 48 months. Kaplan-Meier survival curves were used to assess the risk for failure of the second AM agent.

RESULTS

A total of 64 patients with CLE (78% were women) were included; for 48 patients, the switch was for inefficacy, and for 16, it was for adverse events. Median follow-up was 42 months (range, 3-171). Of the patients changed because of inefficacy, 56% were responders at month 3; however, the response decreased over time, with a median duration before failure of the second AM agent of 9 months (95% confidence interval, 6-24). For patients switched because of adverse events, the second AM agent was well tolerated in 69% of cases.

LIMITATIONS

Retrospective design and subjective evaluation of cutaneous response.

CONCLUSION

A change of AM agent should be considered in patients with CLE when the first AM agent is ineffective or poorly tolerated.

A Critical Review of the Effects of Hydroxychloroquine and Chloroquine on the Eye

Hydroxychloroquine (HCQ) and chloroquine have been used for more than 50 years to treat systemic lupus erythematosus (SLE) and other rheumatic diseases. In general, these drugs are well tolerated and rarely need to be discontinued because of an adverse systemic reaction. However, both medications can be irreversibly toxic to the retina. A new study indicates that toxicity is not as rare as once believed, but depends critically on daily dosage and duration of use, as well as other risk factors. With attention to dosage and other factors, and with proper screening for early signs of toxicity, HCQ can be prescribed with relative safety even over long periods of time.

Quality of life in systemic lupus erythematosus: description in a cohort of French patients and association with blood hydroxychloroquine levels

Objectives

Benefits of hydroxychloroquine (HCQ) use on physician reported outcomes are well documented in systemic lupus erythematosus (SLE). We assess for the first time the association and predictive value of blood HCQ levels towards health-related quality of life (HRQOL) in SLE.

Methods

Data from the PLUS study (a randomized, double-blind, placebo-controlled, multicentre study) were utilized. Blood HCQ levels were quantified by high-performance liquid chromatography along with HRQOL assessments (Medical Outcomes Study-SF-36) at baseline (V1) and month 7 (V2).

Results

166 SLE patients’ data were analysed. Mean (SD) age and disease duration were 44.4 (10.7) and 9.3 (6.8) years. Eighty-seven per cent were women. Mean (SD, median, IQR) HCQ concentrations in the blood at V1 were 660 (314, 615, 424) ng/ml and increased to 1020 (632, 906, 781) ng/ml at V2 (mean difference 366 units, 95% confidence interval −472 to −260, p < 0.001). No significant correlations between HCQ concentrations with HRQOL domains at V1 or V2 were noted. There were no differences in HRQOL stratified by HCQ concentrations. HCQ concentrations at V1 or changes in HCQ concentration (V2-V1) were not predictive of HRQOL at V2 or changes in HRQOL (V2-V1).

Conclusions

No association of HCQ concentrations with current or longitudinal HRQOL were found in SLE.

Determinants of hydroxychloroquine blood concentration variations in systemic lupus erythematosus

OBJECTIVE

Blood concentrations of hydroxychloroquine (HCQ) vary widely among patients with systemic lupus erythematosus (SLE). A pharmacokinetic/pharmacodynamic relationship has been found in different situations, and a very low blood concentration of HCQ is a simple marker of nonadherence to treatment. Therefore, interest in blood HCQ concentration measurement has increased, but little is known about factors that influence blood HCQ concentration variability. This study was undertaken to analyze determinants of blood HCQ concentrations.

METHODS

We conducted a retrospective analysis of patient data, including data from the Plaquenil Lupus Systemic (PLUS) study, to determine the association of epidemiologic, clinical, and biologic factors with blood HCQ concentrations. Data for nonadherent patients (blood HCQ concentration <200 ng/ml) were excluded.

RESULTS

To examine homogeneous pharmacologic data, we restricted the analyses of the PLUS data to the 509 SLE patients receiving 400 mg/day. We found no association of ethnicity or smoking with blood HCQ concentrations and no pharmacokinetic drug-drug interaction with antacids or with inhibitors or inducers of cytochrome P450 enzymes. On multivariate analysis, high body mass index (P = 0.008), no treatment with corticosteroids (P = 0.04), increased time between the last tablet intake and measurement of blood HCQ concentrations (P = 0.017), low platelet count (P < 0.001), low neutrophil count (P < 0.001), and high estimated creatinine clearance (P < 0.001) were associated with low blood HCQ concentrations. In 22 SLE patients with chronic renal insufficiency (median serum creatinine clearance 52 ml/minute [range 23-58 ml/minute]) who received 400 mg/day HCQ, the median blood HCQ concentration was significantly higher than that in the 509 patients from the PLUS study (1,338 ng/ml [range 504-2,229 ng/ml] versus 917 ng/ml [range 208-3316 ng/ml]) (P < 0.001).

CONCLUSION

We provide a comprehensive analysis of determinants of blood HCQ concentrations. Because this measurement is increasingly being used, these data might be useful for clinicians.