title: The Frequency of Scleroderma Renal Crisis over Time: A Metaanalysis.
abstract: Systemic sclerosis (SSc) leads to a high mortality from internal organ involvement. Scleroderma renal crisis (SRC) usually occurs in the diffuse cutaneous SSc (dcSSc) subset early in the disease, often with acute severe hypertension and renal failure. Prevalence of SRC since its classification in the early 1970s was determined in publications to assess whether the prevalence of SRC has changed over time because the proportion with the dcSSc subset is smaller in contemporary cohorts.
  
  
  
  A review of the literature was conducted up to May 2015 using the PubMed, EMBASE, CINAHL, and Cochrane Library databases. Articles were included if they mentioned the prevalence of SRC and were cohort or cross-sectional studies with 50 or more patients with SSc. Articles were excluded if they were not in English or were a case series of SRC or case-control studies.
  
  
  
  Of the 5317 citations identified, 22 qualified. Years of publication were from 1983 to 2011, and cohort size varied from 68 to 8554 patients with SSc totaling 21,908 patients (9248 with dcSSc, 42%). There was no statistical reduction in the temporal prevalence of SRC noticed in the overall patients (4%), patients with dcSSc (7%-9%), or patients with limited cutaneous SSc (lcSSc; 0.5%-0.6%) based on either the start date of the cohort or publication date.
  
  
  
  It appears that SRC remains uncommon in lcSSc and the rate in the dcSSc group may be stable over time. However, increasing awareness of SRC could lead to higher rates in more recent years and/or better survival from SRC, but this was not observed.
authors.affiliation: From the Schulich School of Medicine and Dentistry, University of Western Ontario; St. Joseph's Health Care, London, Ontario, Canada.M. Turk, BSc Candidate, University of Western Ontario; J.E. Pope, MD, MPH, FRCPC, Professor of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, and Division Head Rheumatology, St. Joseph's Health Care.
authors.forename: Matthew
authors.initials: M
authors.lastname: Turk
authors.affiliation: From the Schulich School of Medicine and Dentistry, University of Western Ontario; St. Joseph's Health Care, London, Ontario, Canada.M. Turk, BSc Candidate, University of Western Ontario; J.E. Pope, MD, MPH, FRCPC, Professor of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, and Division Head Rheumatology, St. Joseph's Health Care. janet.pope@sjhc.london.on.ca.
authors.forename: Janet E
authors.initials: JE
authors.lastname: Pope
mesh_terms: D006801:Humans; D015994:Incidence; D015995:Prevalence; D051437:Renal Insufficiency / Q000453:epidemiology* / Q000209:etiology*; D012595:Scleroderma, Systemic / Q000150:complications*
keywords: METAANALYSIS; RENAL CRISIS; SCLERODERMA; SYSTEMIC SCLEROSIS; TEMPORAL TREND