Can more urological deaths in spina bifida be prevented?

The article by Oakeshott et al.1 is another installment in the excellent series of articles from this group over the decades. It reports outcomes at a mean of 46 years old of 117 consecutive infants with open spina bifida who were treated unselectively at the Addenbrooke's Hospital, Cambridge, UK, between 1963 and 1971. Careful assessments of the spinal level of sensory and motor deficits were performed before back closure. The authors now report that urological causes accounted for 28% (22/78) of deaths. Renal failure accounted for 12 deaths and urinary sepsis for six. Two patients died of bladder cancer. Deaths from urological causes occurred only in those with a sensory level of L1 or above (no sensation beneath the inguinal ligament). The authors have made other contributions by studying this cohort that include a previous documentation of kidney disease as an important cause of mortality, the social difficulties encountered by people with spina bifida in adulthood, and the high frequency of sudden and unexpected death in people with spina bifida.

Patients in this cohort were enrolled and followed through the period of the evolution of urological management of people with spina bifida. Lapides et al.2 introduced clean intermittent catheterization for the management of the neurogenic bladder in 1971 and by the mid-1980s, the practice was widely accepted by pediatric urologists. Urodynamics were used to define ‘unsafe’ bladder characteristics that predispose to an adverse renal outcome. Advances in pharmacological and surgical management of the unsafe bladder and its sequelae have resulted in improved preservation of renal function, dryness, and independence for many patients, reviewed by Frimberger et al. (2012);3 but some of the patients studied by Oakeshott et al. are likely to have had renal damage before these advances were thought of and implemented.

The mainstays of prevention of chronic kidney disease (CKD) in spina bifida are early detection by urodynamic studies of the risk factors for the unsafe bladder (high end filling pressure, poor bladder compliance, and high detrusor leak-point pressure), and early detection of vesicoureteral reflux, of renal scarring, of mildly decreased glomerular filtration rate,4 and of bladder and kidney stones, and then prompt management of these problems. Medical risk factors for renal failure that are common in people with spina bifida are diabetes mellitus and hypertension.5 They should also be detected early and treated. Patients themselves need to know early symptoms of pyelonephritis and the importance of seeking help for it. Combinations of factors may also contribute to CKD. These goals are best met in multidisciplinary clinics for adults with spina bifida, of which there are too few.

Why would a higher level of lesion be associated with renal failure? Veenboer et al.6 found that being ‘wheelchair bound’ was associated with unsafe bladder characteristics. Since more people with spina bifida in wheelchairs have a high level of lesion than do ambulatory people with it and since it is thought that an unsafe bladder predisposes to CKD, the report by Veenboer et al. is consistent with the findings of Oakeshott et al.

For patients with spina bifida who develop renal failure, dialysis, and transplantation are just as beneficial as for patients with renal failure but without spina bifida. Ouyang et al.5 from the Centers of Disease Control and Prevention and the University of Alabama used the United States Renal Data System to identify 439 patients with spina bifida and renal failure and matched controls without spina bifida. Patients with spina bifida were younger at the development of renal failure (41 vs 62y) and most commonly had a urological cause of renal failure, in contrast to people without spina bifida who had a medical cause predominantly. Patients with spina bifida on dialysis or who underwent transplantation had similar mortalities to patients without spina bifida, but fewer patients with spina bifida were transplanted (20% vs 30%) and the wait was 1 year longer. Reasons for these differences need to be investigated, but it is the physician's responsibility to be sure that discrimination against people with disabilities is not one of them.

Renal failure was a common cause of death in much younger people before advances in urological management. Oakeshott et al. have done a service by documenting the reemergence of urological causes of death in middle age as important, potentially preventable causes of mortality and identifying a risk factor for them. This emphasizes the need for lifelong multidisciplinary care for people with spina bifida.