Reversible vasospasm of the extremities occurs as an isolated symptom in the absence of underlying disease (primary Raynaud phenomenon) or in association with other disorders (secondary Raynaud phenomenon). It has been reported that Raynaud phenomenon is associated with connective tissue diseases, but the frequency and types of diseases that eventually develop are not well established. Spencer-Green conducted a systematic literature search to assess the rates and predictors of transition to secondary disease after a primary diagnosis of Raynaud phenomenon.
A total of 639 patients with primary Raynaud phenomenon were identified from 10 studies. The average length of study follow-up was four years. The average duration of Raynaud phenomenon in the study subjects was 12.3 years. During follow-up, 12.6 percent (81 patients) developed a secondary disorder. Eighty of these cases were connective tissue diseases. Two thirds of the cases of connective tissue disease were attributed to systemic sclerosis. Systemic lupus erythe-matosus, rheumatoid arthritis or mixed connective tissue disease each occurred in fewer than nine patients.
Transitions to specific connective tissue diseases were infrequent, occurring at a mean rate of 3.2 per 100 patient-years of observation. The mean time from onset of Raynaud phenomenon until development of systemic sclerosis was 10.1 years in patients who developed the disorder. This was no different from the development time for any other secondary disorder. The detailed analysis noted that the best predictor of transition from primary to secondary disease was an abnormal nailfold capillary pattern (positive predictive value: 47 percent). Antinuclear antibody levels in the study subjects had a positive predictive value of only 30 percent. Other diagnostic features such as pulmonary function, presence of digital ulcers and esophageal dysfunction were not statistically predictive of transition.
The author concludes that the analysis was limited by variable entry criteria of diagnostic clinical findings and substantial variation in rates of transition to secondary disease. Despite these limitations, the author notes that, in a clinical practice, the rate and frequency with which secondary connective tissue diseases develop in patients with primary Raynaud phenomenon are low. The best predictor of transition to secondary disease is the presence of abnormalities of the nailfold capillary bed.