title: Increased frequency of ultrasonographic findings suggestive of renal stones in patients with ankylosing spondylitis.
abstract: OBJECTIVE
  To determine the frequency of hypercalciuria and renal stones in ankylosing spondylitis (AS) sufferers.
  
  
  METHODS
  This study involved 83 consecutive AS patients (21 female, 62 male; mean age 36.7 yr), 72 consecutive Behcet's disease (BD) patients (29 female, 43 male; mean age 37.7 yr) as disease control and 92 healthy control (HC) (26 female, 66 male; mean age 32.9 yr.) Twenty-four hour urine analyses for urinary calcium and uric acid levels were performed in each patient. Likewise, blood samples for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), parathyroid hormone (PTH), calcium and uric acid evaluation were taken. Renal ultrasonography to evaluate the presence of renal stone was performed in patients with AS, as well as in the BD patients and HC individuals after a fasting period of 12 hours.
  
  
  RESULTS
  20 of the 80 (25%) patients with AS were diagnosed with renal stones. Only 4/72 (5.5%) BD patients, and 3/98 (3.3%) HC individuals had renal stones by ultrasonography. AS patients had a significantly higher frequency of renal stones compared with BD (p < 0.001) and HC (p < 0.0001). AS patients with renal stones were much older and their disease duration was much longer in comparison with AS patients without renal stones. Ultrasonographic and laboratory findings did not correlate. The number of AS patients with hypercalciuria who had renal stones was higher than that of AS patients who did not have renal stones (p < 0.01). There was a negative correlation between acute phase response and spinal mobility.
  
  
  CONCLUSIONS
  Renal stone prevalence was found to increase in AS patients. The likelihood of renal stone formation was also found to increase with the extension of the disease duration of AS sufferers.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Osmangazi University Medical Faculty, Eskisehir, Turkey. ckorkmaz@ogu.edu.tr
authors.forename: C
authors.initials: C
authors.lastname: Korkmaz
authors.forename: A
authors.initials: A
authors.lastname: Ozcan
authors.forename: N
authors.initials: N
authors.lastname: Akçar
mesh_terms: D000328:Adult; D002118:Calcium / Q000652:urine; D019963:Clinical Chemistry Tests; D005260:Female; D006417:Hematuria / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D007669:Kidney Calculi / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D013997:Time Factors; D014421:Turkey / Q000453:epidemiology; D014463:Ultrasonography
chemical_list: D002118:Calcium