Frequency of Elevated Fecal Calprotectin Levels in Psoriatic Arthritis.
Condition: Psoriatic Arthritis; Inflammatory Bowel Diseases
MeSH terms: Arthritis; Arthritis, Psoriatic; Intestinal Diseases; Inflammatory Bowel Diseases
Study type: Observational

Summary: 
      Background.Recent epidemiologic studies have shown an association between psoriasis,
      psoriatic arthritis (PsA) and inflammatory bowel diseases (IBD). Recently, measurement of
      fecal calprotectin (FC) demonstrated a good sensitivity and specificity for intestinal
      inflammation.

      Primary objective of present study was to evaluate the presence of occult bowel inflammation
      in patients with PsA as expressed by elevated levels of FC. Secondary objectives were to
      investigate the correlation between the levels FC and clinical and laboratory features, and
      the outcome of CF-positive patients in terms of IBD development.
    

Detailed description: 
      A number of studies evaluated the presence of occult intestinal inflammation by using FC
      assay in patients with axial SpA. In 2000, a study conducted in PsA patients without bowel
      symptoms showed at mucosa biopsies the presence of microscopic changes, increase in lamina
      propria cellularity, consisting of plasma cells and lymphocytes, and lymphoid
      aggregates.Present prospective case-control study was designed to investigate occult
      intestinal inflammation by using FC assay in consecutive patients with PsA at onset, and who
      had no abdominal symptoms. Five Italian Centers contributed to patients recruitment adopting
      the same inclusion and exclusion criteria over a 3 year period.

      FC levels were measured at baseline with Bühlmann fCAL Turbo, Switzerland® kit. This
      automated method is a particle enhanced turbidimetric immunoassay employing polyclonal
      antibodies. The manufacturer cut-off for FC positivity was 50 μg/g, with a sensitivity of
      100% and a specificity of 53.1%.

      The number of patients developing IBD was evaluated at the end of follow-up. Clinical and
      laboratory data collection was centralized and two experts statisticians performed the data
      analysis.

      Statistical analysis. All demographic, clinical, and laboratory data were collected and
      descriptive statistics, presented as mean value and standard deviation, were calculated using
      Microsoft ® Office Excel for Windows and ©2019 Minitabs, LLC for Windows. Chi-square test was
      used for categorical variables. FC test sensitivity, specificity, positive (PPV) and negative
      (NPV) predictive values were calculated. Bayes's theorem was used to calculate the 95%
      confidence interval (95%CI). Correlations were calculated using Spearman's correlation (rs).
      P values ≤ 0.05 were accepted as statistically significant.

      The median follow-up was 30 months.
    

Intervention name(s): Fecal calprotectin assay
Intervention type(s): Diagnostic Test
Intervention description(s): FC levels were measured at baseline with Bühlmann fCAL Turbo, Switzerland® kit.
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Both cases and controls were abdominal symptom-free.