Multiple sclerosis and nephrolithiasis: a matched-case comparative study.

OBJECTIVE: To compare stone composition and serum/urine biochemistries in stone formers with multiple sclerosis (MS) against stone formers without MS and to examine the association between mobility, methods of bladder emptying, and stone formation.

PATIENTS AND METHODS: In this retrospective case-control study, we identified patients diagnosed with MS and kidney stone disease who were seen at our institution between 2001 and 2016. For the first part of the study, up to two controls (stone formers without a history of MS) were identified for each case and matched on age, body mass index, and sex. For the second part of this study, matched controls (MS patients without a history of stones) were identified in a 1:1 ratio in a similar fashion. Results of 24-h urine biochemistry studies, stone compositions, serum laboratory measures, medications, history of stone surgeries, mobility, and method of bladder emptying were collected.

RESULTS: In all, 587 patients were identified who had both MS and a history of stone disease. Of these, 118 patients had a stone composition available. When compared to matched controls, patients with MS were significantly more likely to have calcium phosphate stones (42% vs 15%, P < 0.001) and struvite stones (8% vs 3%, P = 0.03) and less likely to have calcium oxalate monohydrate stones (39% vs 64%, P < 0.001). Among those patients with a composition available, those with MS were more likely to have undergone a percutaneous nephrolithotomy (PCNL; 25% vs 12%, P = 0.005) or a cystolithopaxy (16% vs 3%, P < 0.001) compared to their matched controls. In all, 61 patients had a complete 24-h urinary stone panel. There were no significant differences in urinary pH, volume, creatinine, calcium, citrate, oxalate, sodium, and uric acid as well as rates of hypocitraturia, hyperoxaluria, hypercalciuria, and hyperuricosuria among patients with MS. Use of intermittent straight catheterisation [ISC; odds ratio (OR) 3.50, 95% confidence interval (CI) 1.89-6.47]; P < 0.001] or an indwelling catheter (OR 9.78, 95% CI 4.81-19.88; P < 0.001) for bladder emptying was significantly associated with stone disease. There was no association between level of mobility and stone disease (P = 0.10).

CONCLUSIONS: Similar to findings seen in patients with spinal cord injuries, patients with MS have a high incidence of calcium phosphate stones and struvite stones when compared with matched controls. Additionally, they were more likely to undergo PCNL. The method of bladder management appears to be a risk factor in the development of stone disease. These findings suggest the importance of prompt treatment of urinary tract infections in this population and delay the use of ISC, suprapubic tube, or an indwelling Foley, when possible.