The clinical grading of Raynaud's phenomenon and vibration-induced white finger: relationship between finger blanching and difficulties in using the upper limb.

OBJECTIVES

To investigate the association between functional difficulties in using the upper limb and extent and frequency of finger blanching, and the merits of these markers in grading the severity of Raynaud's phenomenon (RP) and vibration-induced white finger (VWF).

METHODS

A questionnaire was mailed to a randomly selected community sample of 22,194 working-aged adults. Information was collected on cold-induced finger blanching--including the extent and frequency of attacks in the past year, and on difficulty in using the upper limb in several everyday activities (e.g. doing up buttons, opening a tight screwtop jar, and pouring from a jug). Associations were examined by logistic regression with the resultant odds ratios converted into prevalence ratios (PRs) and 95% confidence intervals (95% CI).

RESULTS

Among 12,907 respondents were 1,359 who reported finger blanching and provided details of its extent and frequency. Of these, 7.4% reported frequent attacks (50 or more over the year), and 12% reported extensive blanching (affecting nine or ten digits). After adjustment for potential confounders, subjects with finger blanching reported an excess of difficulties in using the limb. Thus, in men with blanching the PR for difficulty with buttons was 4.7 (95% CI 3.9-5.8), and that for pouring from a jug was 3.8 (3.0-4.9) in comparison with men who had never had blanching. Similar associations were found in women and in those men with exposure to hand-transmitted vibration. The risk of reporting difficulties increased markedly with frequency of blanching--up to four- or fivefold in those with 50 or more attacks in the past year compared with those who had none; but differences by extent were less marked, with PRs < or = 1.6 in those with nine to ten digits affected compared with one to two digits.

CONCLUSIONS

RP and VWF are both associated with difficulties in using the upper limb in everyday tasks. Further investigation of potential reporting biases is warranted, but if the associations are causal, frequency of attacks influences impairment more than extent of disease. More account may need to be taken of frequency of blanching episodes in assessing and in compensating subjects with VWF.