A pilot study to determine the optimal timing of the Physician Global Assessment (PGA) in patients with systemic lupus erythematosus

Abstract

The Physician Global Assessment (PGA) is an important and useful outcome measurement of lupus disease activity, but consensus on whether the PGA should be performed prior to or after the receipt of laboratory values is lacking. The objective of this study was to collect preliminary data on the optimal time to perform a PGA. In this pilot study, a PGA was performed by a single clinician upon completion of an outpatient clinical encounter and again after receipt of pertinent laboratory values. Laboratory values obtained at each clinical visit included a CBC, comprehensive chemistries, C3, C4, anti-dsDNA antibody levels, urinalysis and, if pertinent, a spot urinary protein/creatinine ratio. Disease activity was additionally determined by the SELENA-SLEDAI. Fifty-four patients, 3 males and 51 females with an average SLE disease duration of 12.3 (SD 10.5) years contributed 74 assessments to this study. The average SELENA-SLEDAI was 2.2. The average pre-laboratory PGA was 0.46, and the average post-laboratory PGA was 0.55 (p < 0.02 paired Student’s t test). Among the 48 encounters with active disease and a mean SELENA-SLEDAI of 3.37, concordance of the pre-laboratory and post-laboratory PGAs occurred in only third of the patient encounters. Both pre- and post-PGA correlated with the SELENA-SLEDAI. However, the correlation of the post-PGA with the SELENA-SLEDAI was significantly greater than the correlation of the pre-PGA and SELENA-SLEDAI [r = 0.69 vs 0.79, respectively (p < 0.0179)]. In some lupus patients, the PGA determined prior to receipt of laboratory values may be the same as the PGA determined after laboratory values are received. However, in these preliminary data, there was a significant difference between pre-laboratory and post-laboratory PGA with a significantly greater correlation of the post-laboratory PGA with the SELENA-SLEDAI. Further studies in a larger patient population with a greater range of disease activity are needed to confirm and extend these findings.