Retrospective studies in scleroderma: effect of potassium para-aminobenzoate on survival

Demographic and survival data are presented for 390 patients with scleroderma. For the entire group an estimated 81.4% survived 5 years from diagnosis and 69.4% survived 10 years. Life-table analyses revealed that adequate treatment with potassium para-aminobenzoate (Potaba KPAB) was associated with improved survival (p less than 0.01); 88.5% 5 year survival rate and 76.6% 10 year survival rate for adequately treated patients. Five and ten year survival rates for patients never treated with KPAB were 69.8 and 56.6%, respectively. Similar findings were obtained by comparing observed to expected mortality for these patients; again, KPAB therapy showed prolongation of survival. The Cox proportional hazards model was also applied to this retrospective study adjusting for baseline clinical involvement, demographics and KPAB treatment. There were some interesting results including a high significance for skin involvement per se as a prognostic indicator: the greater the extent of skin involvement the poorer prognosis. Time from first diagnosis to first University Hospital visit or admission when included as a covariate did not influence survival.