Table 1

 Baseline demographic and clinical characteristics and laboratory measurements of the 203 patients with systemic lupus erythematosus (SLE), according to compliance status

Total population with SLENon-compliant patientsOther patientsp Value
HCQ, Hydroxychloroquine; SLE, systemic lupus erythematosus,
Values are mean (SD) unless otherwise specified.
We examined the relation between adherence and selected demographic, clinical and biological variables. Access to healthcare was not evaluated because it is available and free for all patients with SLE in France.
Day 0 was the day blood was sampled for the HCQ assays. Immunosuppressive agents included azathioprine, cyclophosphamide, methotrexate and mycophenolate mofetil.
*Severe involvement was defined by renal and neurological involvement.
†Once-daily regimens consisted of 400 mg in a single dose or 200 mg daily. The other patients received 200 mg twice a day.
‡Mean (SD) doses of steroids were calculated among patients taking steroids.
§Mean blood HCQ concentration of patients treated with 200 mg daily (n = 15) was lower than that of patients treated with 400 mg daily (n = 188; 622 (433) and 1037 (525) ng/ml, respectively; p = 0.002).
¶Blood HCQ concentrations ranged from 0 to 129 ng/ml among the 11 patients treated with 400 mg/day of HCQ and from 0 to 87 ng/ml among the 3 patients treated with 200 mg/day of HCQ.
Number of patients20314189
Demographic characteristics
    Age (years)35 (11)30 (6)36 (11)0.06
    Female, n (%)184 (91)13 (93)171 (90)0.62
    Ethnicity, n (%)0.15
        European white134 (66)6 (43)128 (68)0.15
        North African30 (15)5 (36)25 (13)
        Black African/Afro-Caribbean30 (15)3 (21)27 (14)
        Asian8 (4)0 (0)8 (4)
        Hispanic1 (0)0 (0)1 (1)
    Married or living with partner n (%)130 (64)10 (71)120 (63)0.55
    Access to hospital, lives >20 miles away n (%)87 (43)4 (29)83 (44)0.26
    Current smoker n (%)45 (22)3 (21)42 (22)0.62
Clinical characteristics
    Body weight (kg)63 (13)64 (12)63 (13)0.72
    Body mass index (kg/m2)23 (4)23 (4)23 (4)0.58
    Creatinine (μmol/l)77 (18)71 (8)78 (18)0.10
Disease characteristics
    Disease duration (years)8.4 (6.6)6.1 (4.8)8.5 (6.7)0.20
    Severe involvement at SLE onset,* n (%)24 (12)2 (14)22 (12)0.51
    Antiphospholipid syndrome n (%)33 (16)2 (14)31 (16)0.60
    SLE disease activity index on day 03.4 (5.2)8.8 (8.0)3.1 (4.8)0.002
Treatments
    HCQ
        400 mg/day, (%)188 (93)11 (79)177 (94)0.07
        200 mg/day, (%)15 (7)3 (21)12 (6)0.07
        Duration of HCQ treatment (years)5 (4.7)4.1 (4.2)5.1 (4.8)0.06
        Once-daily regimen n (%)†85 (42)7 (50)78 (41)0.52
        Daily dosage (mg/kg/day)6.6 (1.2)6.4 (1.1)6.6 (1.3)0.72
    Prednisone therapy
        Number of patients (%)148 (73)10 (71)138 (73)0.56
        Dose (mg/day)‡12 (10)23 (21)11 (8)0.09
    Immunosuppressive agents n (%)28 (14)4 (29)24 (13)0.11
    Antidepressive agents n (%)27 (13)1 (7)26 (14)0.42
    Total number of oral treatments4.8 (2.2)4.7 (3)4.8 (2.1)0.75
Blood HCQ concentration (ng/ml)1007 (529)§26 (46)¶1079 (473)<0.0001
    Range0–26290–129205–2629