Systemic arterial hypertension in children following renal transplantation: prevalence and risk factors

Background: Control of blood pressure (BP) following renal transplantation may improve allograft and patient survival. Our aims were (i) to describe the distribution of BP and the prevalence of systolic and/or diastolic hypertension in children over the first 5 years following renal transplantation and (ii) to evaluate clinical risk factors and centre-specific factors associated with hypertension in this population.

Methods: We conducted a retrospective case note review of all current paediatric kidney transplant patients in the UK, with data collected at 6 months, 1, 2 and 5 years following transplantation in subjects with hypertension (systolic and/or diastolic BP 95th ) and non-hypertensive subjects BP 95th .

Results: In total, 27.3 (117/428), 27.6 (118/428), 26.0 (95/365) and 25.6 (50/195) of the patients were hypertensive (systolic and/or diastolic BP 95th ) at 6 months, 1, 2 and 5 years following transplantation, respectively. A total of 58.4 of the patients at 6 months, 52.8 at 1 year, 48.2 at 2 years and 48.2 at 5 years were receiving anti-hypertensive therapy, of whom 31.636.6 remained hypertensive. When subjects were identified as being hypertensive, on anti-hypertensive medication or had untreated hypertension (systolic and/or diastolic BP 95th ), 66.4, 61.0, 56.4 and 55.9 of patients were hypertensive at 6 months, 1, 2 and 5 years, respectively. In a multivariate model, odds ratios for systolic hypertension were 4.16 (deceased versus living donor), 2.65 (lowest versus highest quartile of height z-score) and 2.07 (if on anti-hypertensive; yes versus no). There was significant variation in prevalent rates of hypertension between centres (P 0.0001) that remained significant (P 0.003) after adjustment for all the factors in the multivariate model.

Conclusions: Control of BP after kidney transplantation remains sub-optimal in paediatric centres in the UK. Just over 25 of patients remain hypertensive 5 years following transplantation. Significant differences between centres remain unexplained and may reflect differences in assessment and management of hypertension.