Table 3.

Multivariable associations between patient characteristics and not experiencing any blood-test abnormalities^a among those with RA who were prescribed methotrexate, and those with IBD who were prescribed azathioprine^b

Characteristic	Odds ratio	95% CI	P-value
RA/methotrexate cohortc
Age group, years, versus 18–39
40–59	0.79	0.55 to 1.13	0.21
60–79	0.56	0.39 to 0.79	<0.001
≥80	0.26	0.17 to 0.40	<0.001
Sex, versus male
Female	1.11	0.94 to 1.30	0.22
Socioeconomic status, IMD quintile, versus 5 (least deprived)
4	0.95	0.77 to 1.17	0.61
3	0.96	0.77 to 1.20	0.70
2	0.95	0.75 to 1.21	0.69
1 (most deprived)	0.90	0.70 to 1.16	0.40
Long-term conditions
CKD versus no CKD	0.37	0.21 to 0.67	<0.001
CVD versus no CVD	0.51	0.30 to 0.85	0.01
Diabetes type 1 or 2 versus no diabetes	0.66	0.51 to 0.83	<0.001
Hypertension versus no hypertension	0.93	0.79 to 1.10	0.41
IBD/azathioprine cohortd
Age group, years, versus 18–39
40–59	1.35	1.03 to 1.79	0.03
60–79	0.65	0.45 to 0.93	0.02
≥80	0.09	0.01 to 0.33	0.002
Sex, versus male
Female	0.96	0.75 to 1.22	0.72
Socioeconomic status, IMD quintile, versus 5 (least deprived)
4	1.41	0.99 to 2.01	0.06
3	0.90	0.63 to 1.28	0.55
2	0.83	0.57 to 1.22	0.34
1 (most deprived)	0.85	0.57 to 1.26	0.41
Long-term conditions
CKD versus no CKD	0.39	0.17 to 0.82	0.02
Diabetes type 1 or 2 versus no diabetes	0.57	0.35 to 0.94	0.03
Hypertension versus no hypertension	0.91	0.61 to 1.36	0.64

^a Using NICE-specified thresholds and tests (test thresholds: WBC ≥3.5×10⁹/L; MCV ≤105 fL; neutrophils ≥1.6×10⁹/L; platelets ≥140×10⁹/L; eosinophils ≤0.5×10⁹/L; ALT ≤100 U/L; AST ≤100 U/L; albumin ≥30 g/L; and eGFR ≥60 ml/min/1.73 m²).

^b Models adjusted for age, sex, socioeconomic status, and long-term conditions. Small numbers with CVD and heart failure in the IBD azathioprine group meant this condition combination was not included in the multivariable model as it was for the RA/methotrexate group.

^c Patients with prevalent and incident RA prescribed methotrexate in any 2-month period over the study period.

^d Patients with prevalent and incident IBD prescribed azathioprine in any 2-month period over the study period. ALT = alanine aminotransferase. AST = aspartate transaminase. CKD = chronic kidney disease (excluding dialysis and transplant). CVD = cardiovascular disease (including ischaemic heart disease, cerebrovascular disease, heart failure, and peripheral vascular disease). eGFR = estimated glomerular filtration rate. IBD = inflammatory bowel disease. IMD = Index of Multiple Deprivation. MCV = mean cell volume. NSAID = non-steroidal anti-inflammatory drug. RA = rheumatoid arthritis. WBC = white blood cell.