Determining the optimal method for proteinuria detection in chronic spinal cord injury

Screening for proteinuria in 'at-risk' patients with spinal cord injuries: lessons learnt from failure

Spinal cord injury patients may develop proteinuria as a result of glomerulosclerosis due to urosepsis, hydronephrosis, vesicoureteric reflux, and renal calculi. Proteinuria in turn contributes to progression of kidney disease. We report one paraplegic and two tetraplegic patients, who developed recurrent urine infections, urinary calculi, and hydronephrosis. These patients required several urological procedures (nephrostomy, cystoscopy and ureteric stenting, ureteroscopy and lithotripsy, extracorporeal shock wave lithotripsy). These patients had not received antimuscarinic drugs nor had they undergone video-urodynamics. Proteinuria was detected only at a late stage, as testing for proteinuria was not performed during follow-up visits. Urine electrophoresis showed no monoclonal bands in any; Serum glomerular basement membrane antibody screen was negative. Serum neutrophil cytoplasmic antibodies screen by fluorescence was negative. All patients were prescribed Ramipril 2.5 mg daily and there was no further deterioration of renal function.

Spinal cord injury patients, who did not receive antimuscarinic drugs to reduce intravesical pressure, are at high risk for developing reflux nephropathy. When such patients develop glomerulosclerosis due to recurrent urosepsis, renal calculi, or hydronephrosis, risk of proteinuria is increased further. Take home message: (1) Screening for proteinuria should be performed regularly in the ‘at-risk’ patients. (2) In the absence of other renal diseases causing proteinuria, spinal cord injury patients with significant proteinuria may be prescribed angiotensin-converting enzyme inhibitor or angiotensin-II receptor antagonist to slow progression of chronic renal disease and reduce the risk of cardiovascular mortality.

Prevalence of chronic kidney disease in patients with spinal cord injuries/disorders

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) and spinal cord injury and disorders (SCI/D) are common and costly conditions among Veterans. However, little is known about CKD among adults with SCI/D.

METHODS

We conducted cross-sectional analyses of Veterans with SCI/D across all VA facilities in 2006. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) and categorized by standard eGFR strata. eGFR was calculated in two ways: (a) the Modification of Diet in Renal Disease (MDRD) equation and (b) the MDRD equation + an empirically derived correction factor for SCI/D (MDRD-SCI/D). Logistic regression models were used to examine the relationship between patient characteristics and CKD.

RESULTS

Among 9,333 SCI/D Veterans with an available eGFR, the proportion with CKD was substantially higher based on the MDRD-SCI/D equation (35.2%) than based on the MDRD equation (10.2%). In adjusted analyses, while older age (OR for >65 years = 2.53; 95% CI: 2.21-2.89), female sex (OR 2.18; 95% CI: 1.62-2.92), and a non-traumatic cause for injury (OR 1.39; 95% CI: 1.23-1.57) were associated with an increased odds of CKD, black race (OR 0.64; 95% CI: 0.56-0.72) and a duration of injury of ≥10 years (OR 0.76; 95% CI: 0.67-0.86) were associated with a decreased odds of CKD. Diagnostic codes for CKD and nephrology visits were infrequent for SCI/D Veterans with CKD (27.51 and 6.58%, respectively).

CONCLUSION

Using a recently validated version of the MDRD equation with a correction factor for SCI/D, over 1 in 3 Veterans with SCI/D had CKD, which is more than 3-fold higher than when traditional MDRD estimation is used.