Polyneuropathy in kidney transplant recipients: a cross-sectional study in Groningen, the Netherlands

To determine the prevalence and clinical characteristics associated with polyneuropathy in kidney transplant recipients (KTRs).

Cross-sectional study.

SENS study at the University Medical Center Groningen, the Netherlands, December 2021-May 2023.

KTR, participating in the ongoing TransplantLines Biobank and Cohort Study, ≥12 months post-transplantation.

Participants underwent a structured neurological assessment including history taking, neurological examination, quantitative sensory testing and nerve conduction studies. An expert panel classified participants into no/possible, probable/definite large fibre polyneuropathy or small fibre neuropathy. Large-fibre subtypes included axonal or demyelinating, pure sensory, pure motor and sensorimotor. To assess potential associations with clinical characteristics, logistic regression analysis was conducted.

We included 160 KTRs with a mean age of 59.8±11.6 years at a median of 6.1 (95% CI 3.9 to 13.1) years post-transplantation, with 16 KTRs (10%) diagnosed with polyneuropathy before study inclusion. In total, 84 KTRs (53%) were identified with large fibre polyneuropathy and 7 KTRs (4%) with small fibre neuropathy. KTRs with large fibre polyneuropathy presented with either sensor-predominant polyneuropathy (40 KTR (48%)) or sensorimotor polyneuropathy (44 KTR (52%)). We found no neurophysiological characteristics of demyelination. Overall, 18% (95% CI 11% to 27%) of KTRs with large fibre polyneuropathy were asymptomatic. Higher age (OR=1.04 (1.01 to 1.08), p=0.01), male sex (OR=2.55 (1.19 to 5.60), p=0.02), diabetes (OR=5.58 (1.36 to 38.14), p=0.03) and elevated urea levels (OR=1.12 (1.04 to 1.23), p=0.01) were significantly associated with polyneuropathy in KTR.

In contrast with previous studies, axonal sensory or sensorimotor polyneuropathy is highly prevalent and often underdiagnosed in KTR. Next to higher age and male sex, it was independently associated with diabetes and higher urea levels. Further research is needed to reveal the aetiology and course of polyneuropathy in KTRs.

NCT04664426.