Pin-prick (Medipin) assessment for neuropathy in diabetes: prospective screening study in primary care

Highlights • Screening for diabetic neuropathy is indicated to minimise patient complications. • Monofilament testing of feet is used most in primary care despite test limitations. • The Medipin device allows safe pin-prick testing to screen for small nerve function. • Compared to monofilament, Medipin diagnoses more patients with nerve impairment. • Due to role in pain perception, small nerve testing may benefit diabetic patients. Abstract Aims: Diabetic patients are at elevated risk of neuropathy; early detection is desirable to minimise the risk of complications. The Medipin pin-prick device was appraised as a screening tool for diabetic neuropathy. Methods: Prospective cross-sectional comparative screening study in primary care setting, involving 389 participants with type 2 diabetes mellitus. The Medipin pin-prick method, involving dorsal application on the hallux of both feet, was compared to 10 g monofilament testing. Results: The ternary and semi-quantitative approach for scoring Medipin pin-prick sensation give very similar results (Spearman rho 0.67, P < 0.001). A total of 59 % patients had no signs of neuropathy (sharp sensation), 38 % reported impaired sensation (dull sensation), and an absence of sensation occurred in 3 % of patients. For the monofilament dorsal method, the figures were 79 % no neuropathy, 14 % elevated risk, and 7 % neuropathy respectively, and with the monofilament plantar method 87 % of patients had no neuropathy and 13 % did. Correlation analyses showed that taller patients and those with existing neuropathic pain are at very modest increased risk of neuropathy. Conclusions: The Medipin pin-prick device can identify diabetic neuropathy and detects (first signs of) neuropathy in relatively more patients than 10 g monofilament testing. The differential targeting of nerve types, namely predominant small (Medipin) versus large (monofilament) fibre, likely underpins the difference in outcomes.