Table 1.
Characteristics of the study population
| Characteristic | Exposed, N=8,999 | Unexposed, N=24,118 |
|---|---|---|
| Age (years) | 56 (46–66) | 55 (45–65) |
| Female, n (%) | 6,909 (76.8) | 18,536 (76.9) |
| “Start date” | April 2010 (August 2006–October 2012) | Dec 2009 (May 2006–May 2012) |
| Duration of follow-up after “start date” (days) | 1,509 (848–2,595) | 1,475 (1,071–2,285) |
| Time between the end of exposure and the end of follow-up (days) | 5 (0–202) | – |
| Dosage (mg/day) | ||
| HCQ | 307 (238–377) | – |
| CQ | 169 (132–234) | – |
| Underlying diseases, n (%) | ||
| Rheumatoid arthritis | 6,139 (68.2) | 15,995 (66.3) |
| Systemic lupus erythematosus | 1,644 (18.3) | 4,932 (20.4) |
| Sjogren syndrome | 603 (6.7) | 1,657 (6.9) |
| Dermatomyositis/polymyositis | 29 (0.3) | 26 (0.1) |
| Other connective tissue diseasesa | 531 (5.9) | 1,358 (5.7) |
| Light eruption | 53 (0.6) | 150 (0.6) |
| Number of prescriptions ofb | ||
| Methotrexate | 0 (0–71) | 0 (0–50) |
| Azathioprine | 0 (0–2) | 0 (0–0) |
| Glucocorticoids | 2 (0–60) | 0 (0–34) |
| NSAIDs | 11 (0–108) | 5 (0–85) |
| Metformin | 0 (0–13) | 0 (0–10) |
| Vitamin D | 0 (0–43) | 0 (0–25) |
| Smoking status, n (%) | ||
| Nonsmokers | 4,133 (45.9) | 11,800 (48.9) |
| Ex-smokers | 2,878 (32.0) | 6,657 (27.6) |
| Smokers | 1,723 (19.2) | 5,090 (21.1) |
| Missing | 265 (2.9) | 571 (2.4) |
| Townsend deprivation index, n (%) | ||
| 0 (less deprived) | 398 (4.4) | 897 (3.7) |
| 1 | 2,304 (25.6) | 6,540 (27.1) |
| 2 | 1,956 (21.8) | 5,284 (21.9) |
| 3 | 1,809 (20.1) | 4,675 (19.4) |
| 4 | 1,496 (16.6) | 3,961 (16.4) |
| 5 (more deprived) | 930 (10.3) | 2,483 (10.3) |
| Missing | 106 (1.2) | 278 (1.2) |
| BMI (kg/m2) | 26.7 (23.4–31.0) | 26.6 (23.4–30.8) |
| Past history of, n (%) | ||
| Non-skin cancer | 431 (4.8) | 1,063 (4.4) |
| Hematological malignancy | 64 (0.7) | 112 (0.5) |
| Skin cancer | 277 (3.1) | 751 (3.1) |
| Hypertension | 2,401 (26.7) | 5,852 (24.3) |
| Diabetes | 840 (9.3) | 1,943 (8.1) |
Notes:
a
Systemic sclerosis, antiphospholipid syndrome, mixed and undifferentiated connective tissue diseases.
b
Before the date of cancer with those with cancer and before a randomly selected date during follow-up for those without cancer. Continuous variables are reported as medians and interquartile range except for the number of medication prescriptions that are reported as medians and 5th–95th percentile range.
Abbreviations: BMI, body mass index; CQ, chloroquine; HCQ, hydroxychloroquine; NSAIDs, nonsteroidal antiinflammatory drugs,