Egyptian patients with axial spondyloarthritis: The frequency and predictors of renal impairment

Aim of the work

To determine the frequency of and risk factors for renal impairment in patients with axial spondyloarthritis (axSpA).

Patients and methods

Fifty axSpA patients participated in this study. In accordance with the Kidney Disease Outcomes Quality Initiative (K/DOQI) criteria, patients were split into two groups: group 1comprised renal impairment and group 2 comprised non-renal impairment. The ankylosing spondylitis (AS) disease activity score (ASDAS), Bath AS disease activity index (BASDAI) and estimated glomerular filtration rate were assessed.

Results

The mean age of patients was 38.9 ± 11.7 years, males were 54 % and the disease duration was 11.36 ± 6.1 years. The mean ASDAS score was 5.58 ± 1.38 and BASDAI was 5.18 ± 1.55. The eGFR was 76.4 ± 36.2 ml/min/1.73 m² and 28 % had positive human leucocytic antigen (HLA-B27). 80 % were receiving biologic therapy. Nephropathy by ultrasound and renal impairment were detected in 34 % and 52 % of the cases respectively. The cumulative dose of non-steroidal anti-inflammatory drugs (NSAIDs), C-reactive protein, erythrocyte sedimentation rate, low density cholesterol, blood urea nitrogen, creatinine, proteinuria, ASDAS and BASDAI were significantly higher in those with renal impairment(p = 0.0001, p = 0.0001, p = 0.001, p = 0.035, p = 0.0001, p = 0.0001, p = 0.0001, p = 0.001, p = 0.001 respectively) while the eGFR and high density lipoprotein were significantly lower (p = 0.001and p = 0.02). Only the cumulative dose of NSAIDs was a significantly independent variable influencing the development of renal impairment (OR=1.01, CI; 1.001–1.02, p = 0.024) at cut-off level > 1166.3 g.

Conclusions

Renal impairment is frequent in axSpA patients with decreased eGFR and high disease activity. The cumulative dose of NSAIDs is a significant predictor of renal impairment.