Session Information
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose: Hydroxychloroquine (HCQ) is recommended for all patients with SLE. While patient reported adherence rates are between 51-64%, blood HCQ level testing may be a more accurate measure of compliance. This study aimed to evaluate the role and feasibility of blood HCQ level monitoring in a predominantly Hispanic, socioeconomically disadvantaged SLE cohort.
Methods : This is a cross-sectional study of SLE patients treated with HCQ 200–400 mg/day at the Columbia University Lupus Center. HCQ levels were measured from samples obtained during routine blood draws by high performance liquid chromatography (Avise HCQ, Exagen Diagnostics ©). Patients on HCQ for ≥ 6 months were included; patients who admitted to non-adherence before testing were excluded. Differences in demographic and clinical features between patients with therapeutic and sub-therapeutic levels were evaluated.
Results : 55 patients had blood HCQ levels tested. 50 (90.9%) were women, 41 (74.5%) Hispanic, and 8 (14.5%) Black. 46 (83.6%) resided in the Bronx or Washington Heights; 41 (74.5%) were insured by public assistance programs. 28 (50.9%) were on additional immunosuppressants; 8 (14.6%) had abnormal renal function. The mean SLEDAI was 4.7 (range 0-20). Therapeutic blood HCQ is considered to be ≥ 1000 ng/mL based on prior data; in this cohort, median HCQ level was 722 (range 0-2466 ng/mL); 34 (61.8%) patients had sub-therapeutic levels (mean 346.6 ng/mL), and 10 (18.2%) had undetectable levels. Hispanic ethnicity and normal renal function were associated with sub-therapeutic HCQ. Patients on mycophenolate mofetil (MMF) for any indication were more likely to have therapeutic HCQ (Table). In a subset of patients on MMF with concurrent mycophenolate levels (n=7), the two drug levels correlated (r=0.544). Median SLEDAI scores were 2 in patients with therapeutic HCQ vs. 5 in sub-therapeutic patients (p=0.066). SLEDAI scores inversely correlated with HCQ levels (r= -0.326).
Conclusion : 62% of SLE patients in this cohort had sub-therapeutic HCQ levels despite self-reported adherence, suggesting that blood HCQ testing may be more accurate at assessing compliance. Low HCQ levels were associated with increased SLE activity; routine testing of HCQ levels and compliance counseling—especially when immunosuppression is withdrawn—is likely to improve outcomes. Future studies are needed to identify how genetics, renal clearance, and MMF might affect HCQ’s pharmacokinetics.
| Total Population with SLE | Therapeutic (≥1000ng/mL) | Sub-therapeutic (<1000ng/mL) | p-value | |
| Number of patients |
55 |
21 |
34 |
|
| HCQ level (ng/ml) ± SEM |
765.6 ± 85.1 |
1444.0 ± 54.3 |
346.6 ± 78.2 |
|
| HCQ level = 0 n (%) |
10 (18.2) |
10 (29.4) |
||
| HCQ dosage | ||||
|
400mg n (%) |
50 (90.9) |
21 (100) |
29 (85.3) |
|
|
200-300mg n (%) |
5 (9.1) |
0 (0) |
5 (14.7) |
|
| Age (years) ± SEM |
38.3 ± 1.8 |
37.0 ± 2.4 |
39.1 ± 2.7 |
NS |
| Female n (%) |
50 (90.9) |
20 (95.2) |
30 (88.2) |
NS |
| Ethnicity | ||||
|
Hispanic n (%) |
41 (74.5) |
12 (57.1) |
29 (85.3) |
0.020 |
|
Non-Hispanic n (%) |
14 (25.4) |
9 (42.9) |
5 (14.7) |
|
| Body mass index (kg/m2) ± SEM |
28.8 ± 0.8 |
29.3 ± 1.1 |
28.5 ± 1.3 |
NS |
| New York City Neighborhood | ||||
|
Bronx n (%) |
22 (40.0) |
9 (42.9) |
13 (38.2) |
NS |
|
Washington Heights n (%) |
24 (43.6) |
8 (38.1) |
16 (47.1) |
NS |
|
Other n (%) |
9 (16.4) |
4 (19.0) |
5 (14.7) |
NS |
| Smoking n (%) |
6 (10.9) |
3 (14.3) |
3 (8.8) |
NS |
| Normal eGFR >60 n (%) |
47 (85.5) |
15 (71.4) |
32 (94.1) |
0.020 |
| SLEDAI (IQR) |
3 (0.5, 7) |
2 (0,5) |
5 (2,8) |
0.066 |
| Rheumatologist | ||||
|
Attendings n (%) |
19 (34.5) |
9 (42.9) |
10 (29.4) |
NS |
|
Fellows n (%) |
36 (65.5) |
12 (57.1) |
24 (70.6) |
|
| Insurance | ||||
|
Private n (%) |
14 (25.5) |
8 (38.1) |
6 (17.6) |
0.091 |
|
Public n (%) |
41 (74.5) |
13 (61.9) |
28 (82.4) |
|
| Immunosupressants n (%) |
28 (50.9) |
14 (66.7) |
14 (41.2) |
0.066 |
|
MMF |
16 (29.1) |
10 |
6 |
0.017 |
|
MTX |
3 (5.5) |
0 |
3 |
NS |
|
AZA |
6 (10.9) |
3 |
3 |
NS |
|
Other |
3 (5.5) |
1 |
2 |
NS |
| Prednisone n (%) |
19 (34.5) |
10 (47.6) |
9 (26.5) |
NS |
To cite this abstract in AMA style:
Miceli J, Neville K, Geraldino-Pardilla L, Askanase AD. Hydroxychloroquine Blood Level Monitoring in a Predominantly Hispanic Systemic Lupus Erythematosus Cohort [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/hydroxychloroquine-blood-level-monitoring-in-a-predominantly-hispanic-systemic-lupus-erythematosus-cohort/. Accessed .« Back to 2016 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/hydroxychloroquine-blood-level-monitoring-in-a-predominantly-hispanic-systemic-lupus-erythematosus-cohort/