Assessment of diabetic polyneuropathy in Zanzibar: Comparison between traditional methods and an automated point-of-care nerve conduction device

Highlights • We screened for signs of neuropathy in a diabetes population in Zanzibar. • Nerve conduction study by NC-stat DPNCheck found neuropathy in 45%. • Monofilament results suggestive of neuropathy in 61%. • Compared to nerve conduction study, monofilament had a 59% specificity. • Hyperglycaemia and hypertension are highly prevalent risk factors in this population.
Aim Scant information is available about the prevalence of diabetic polyneuropathy, as well as the applicability of screening tools in sub-Saharan Africa. We aimed to investigate these issues in Zanzibar (Tanzania). Methods One hundred consecutive diabetes patients were included from the diabetes clinic at Mnazi Mmoja Hospital. Clinical characteristics were recorded. Further, we investigated: a) self-reported numbness of the lower limbs, b) ten-point monofilament test, c) the Sibbald 60-s Tool and d) nerve conduction studies (NCS, using an automated handheld point-of-care device, the NC-stat DPNCheck). Results Mean age was 54 years, 90% had type 2 diabetes, and with 9 year average disease duration. Mean HbA1c was 8.5% (69 mmol/mol), blood pressure 155/88 mmHg. Sixty-two% reported numbness, 61% had positive monofilament and 79% positive Sibbald tool. NCS defined neuropathy in 45% of the patients. Only the monofilament showed appreciable concordance with the NCS, Cohen’s κ 0.43. Conclusions The patient population was characterised by poor glycaemic control and hypertension. In line with this, neuropathy was rampant. The monofilament test tended to define more cases of probable neuropathy than the NCS, however specificity was rather low. Plantar skin thickening may have led to false positives in this population. Overall concordance was, however, appreciable, and could support continued use of monofilament as a neuropathy screening tool. The NC-stat DPNCheck could be useful in cases of diagnostic uncertainty or for research purposes in a low resource setting.