Risk factors for urolithiasis in patients with ankylosing spondylitis: a prospective case–control study

Abstract

It has been reported that renal stone formation increased in patients with ankylosing spondylitis (AS). However, its reason remains unclear. The aim of this study was to evaluate serially the possible risk factors for renal stone formation in AS patients. Two groups consisted of AS patients with renal stone (n = 30), AS patients without renal stone (n = 30), and 20 healthy controls (HC) were included to the study. Parathyroid hormone, calcium, magnesium, phosphorus and immunoglobulin A levels and 24 h urine were evaluated at baseline, and three times monthly. Serum calcium levels were higher in AS patients with urolithiasis than those without at baseline and third-month evaluation (baseline: 9.53 ± 0.3 vs 9.32 ± 0.3 mg/dl; p < 0.03; at third-month evaluation: 9.74 ± 0.2 vs 9.56 ± 0.3 mg/dl; p < 0.01). No significant differences were found between groups in terms of PTH and magnesium levels. In all evaluation times, although urinary calcium excretion was higher in AS patients with urolithiasis than in those without, it did not reach a statistical significance. IgA levels were significantly higher in renal stone sufferers than HC patients in all evaluation times.AS patients with urolithiasis also had high IgA levels compared with AS patients without renal stone at the second-month evaluation time (276 ± 102 vs 219 ± 104 mg/dl, p < 0.002). Increased levels of serum calcium and IgA levels as well as family history for urolithiasis may be an indicator of the development of urolithiasis in AS patients.

Nephrolithiasis in Ankylosing Spondylitis and its Relation with Disease Assessment Scales

“…Although this study did not reach statistical significance, the authors also found high urinary calcium levels compared to patients who did not have calculi. They concluded that a subgroup of AS patients tend to have high blood and urinary calcium and that these biochemical abnormalities and other factors might be responsible for the development of urolithiasis [11]. Our study was not in line with their trial as we could not find any significant difference in the blood level of calcium, phosphorus, Vitamin D, parathormone, and urinary calcium excretion.…”

“…Here with the pathologi- cal process of resorption, the predominance of formation phase in the bone cycle could also affect the formation of renal calculi [24]. In a recent prospective study, Gonullu et al found a significantly higher level of blood calcium at the baseline in AS patients with compared to AS patients without renal calculi [11]. Although this study did not reach statistical significance, the authors also found high urinary calcium levels compared to patients who did not have calculi.…”

“…An extra-articular involvement is common in inflammatory diseases. Although renal involvement has been shown in many studies on AS, the number of studies investigating the coexistence of renal calculi in AS is very limited [7][8][9][10][11][12][13].…”

“…Several studies showing an increased incidence of renal calculi in patients with AS have been published [7][8][9][10][11][12][13]. Jacobsen et al found the risk of nephrolithiasis in patients with AS to be more than twofold compared to the general population.…”

Helper T‐cell signaling and inflammatory pathway lead to formation of calcium phosphate but not calcium oxalate stones on Randall's plaques

“…We previously found that suppression of the NF‐κB signal reduces the risk for crystal formation in human renal tubular cells . In addition, although the relationship between kidney stone formation and the role of immunoglobulins is not well understood, the correlation between immunoglobulin A and the risk of urolithiasis, as well as a possible immunoglobulin treatment for atherosclerosis, have been reported …”