Lumbosacral radiculoplexus neuropathy: Incidence and the association with diabetes mellitus.

OBJECTIVE: To determine the previously unknown incidence of lumbosacral radiculoplexus neuropathy (LRPN) and its association with diabetes mellitus (DM).

METHODS: LRPN defined by clinical and electrophysiologic criteria was identified among Olmsted County, Minnesota, residents during a 16-year period (2000-2015) using the unique facilities of the Rochester Epidemiology Project. DM was ascertained using American Diabetes Association criteria.

RESULTS: Of 1,892 medical records reviewed, 59 patients (33 men, 26 women) were identified as having LRPN. The median age was 70 years (range 24-88 years) and the median time of onset of symptoms to diagnosis was 2 months (range 1-72 months). DM was more frequent in patients with LRPN than in controls (39/59 vs 35/177, p < 0.001) but not in those with pre-DM (10/20 vs 55/142, p = 0.336). LRPN recurred in 3 patients with DM resulting in 62 LRPN episodes during the study period. The overall incidence of LRPN was 4.16/100,000/y (95% confidence interval [CI] 3.13-5.18). The incidences of LRPN among DM and non-DM groups were 2.79/100,000/y (95% CI 1.94-3.64) and 1.27/100,000/y (95% CI 0.71-1.83), respectively. The odds of LRPN among patients with DM and pre-DM was 7.91 (95% CI 4.11-15.21) and 1.006 (95% CI 1.004-1.012), respectively.

CONCLUSIONS: LRPN incidence in Olmsted County of 4.16/100,000/y makes LRPN a common inflammatory neuropathy and is higher than that of other immune-mediated neuropathies (acute or chronic inflammatory demyelinating polyradiculoneuropathy, brachial plexus neuropathy) assessed within the same population. DM is a major risk factor for LRPN and thus justifies the continued classification of LRPN into diabetic and nondiabetic forms.