To study cardiovascular autonomic nervous functions in patients with rheumatoid arthritis (RA) compared with controls and to investigate fasting and meal stimulated pancreatic polypeptide (PP) in RA and its possible associations with autonomic functions and disease activity.
Forty-three women meeting the American Rheumatism Association 1987 diagnostic criteria for RA and 61 healthy controls were studied. Blood pressure recordings and cardiovascular heart rate studies were performed. PP was measured by radioimmunoassay.
Cardiovascular reflexes were equal in the 2 groups, but the patients had significantly higher fasting plasma PP level with mean log10 value of 0.94 pmol/l (SD = 0.38) compared with 0.68 pmol/l (SD = 0.35) in the controls (p = 0.0006). Mean log10 plasma PP increase 30 min after the meal was 1.80 pmol/l (SD = 0.42) for the patient group and 1.47 pmol/l (SD = 0.40) in the controls (p = 0.0001). Feeding caused a mean PP increase of 1.85 (SD = 0.42) for the patients and 1.44 (SD = 0.42) in the controls 60 min postprandially (p = 0.0001). Multiple regression and correlation analysis showed no association between PP and disease activity.
The higher basal and postprandial PP in the RA group indicates a relationship between the disease and PP by unknown mechanisms.