Nocturnal enuresis in school-aged children with sickle-cell anemia: Any relationship with hyposthenuria?

Reports show that children with sickle-cell anemia (SCA) have a tendency for nocturnal enuresis when compared with their counterparts with normal hemoglobin. Although nocturnal enuresis in SCA has been attributed to several factors including tubular and even bladder dysfunction, its relationship with hyposthenuria has been questioned in some studies.

The study aims to determine the relationship of hyposthenuria with nocturnal enuresis seen in school-aged children with SCA.

A cross-sectional study of seventy school-aged children with SCA, who met the study criteria and seventy age- and gender-matched controls was conducted at the Sickle-cell Clinic, University of Nigeria Teaching Hospital in Enugu, Southeast Nigeria. The diagnosis of enuresis among the subjects and controls was based on the Diagnostic and Statistical Manual of Mental Disorders-IV criteria while urine specific gravity (USG) was determined on dipstick urinalysis. The frequencies of categorical variables were compared using Chi-square test or Fisher exact test as appropriate and the means of continuous variables with Student's t-test. The level of statistical significance was taken as P< 0.05.

The prevalence of hyposthenuria was 4.5% and 8.3% among enuretic and nonenuretic subjects respectively, 6.7% and 10.9% among enuretic and nonenuretic controls and 4.5% and 6.7% among enuretic subjects and controls, respectively. The differences were not statistically significant. The mean ± standard deviation USG was significantly higher in the subjects than in the controls (1.02 ± 0.01 vs. 1.01 ± 0.01, P = 0.013) and enuretic subjects than enuretic controls (1.02 ± 0.01 vs. 1.01 ± 0.01, P = 0.007). The prevalence of nocturnal enuresis was significantly higher in male subjects compared to female subjects (odds ratio [OR] [95% confidence interval (95% CI)] =8.14 (2.12, 31.24), χ2 = 12.21, P< 0.001) and male controls (χ2 = 5.57, P = 0.018). Enuretic subjects had a significantly higher prevalence of parental history of childhood enuresis (OR [95% CI] =10.39 [2.45, 44.05], P< 0.002) than the enuretic controls. The relationship between the enuretic subjects and controls with respect to age of attainment of urinary control, family size, socioeconomic class, and sibling history of enuresis were not statistically significant.

Nocturnal enuresis in children with SCA may not be related to hyposthenuria. However, male gender and parental history of childhood enuresis are significant risk factors.