Inflammatory markers and the progression of IgA glomerulonephritis.

BACKGROUND

IgA glomerulonephritis (IgAGN) composes a variable prognosis with 15-40% of the patients eventually progressing to end-stage renal failure. Known risk factors for progressive course of IgAGN include hypertension, proteinuria and renal insufficiency. Although markers of inflammation such as serum or urinary interleukin-6 (IL-6) and serum albumin have predicted progression in some studies, sensitive CRP (hs-CRP) has not been directly linked to the progression of IgAGN.

METHODS

A total of 174 (70 females) patients were invited for two visits 11 and 16 years (medians) after IgAGN was diagnosed in renal biopsy. All patients had been diagnosed at least 5 years before the first visit. Progressive disease was defined as cystatin-C exceeding normal limits and showing over 20% elevation between the visits, or kidney transplantation or start of dialysis. Cystatin-C and creatinine clearance, serum hs-CRP, s-albumin, s-IL-6 and white blood cell count (WBC) were available for analysis from 118 patients.

RESULTS

IgAGN was progressive in 19.5% of the patients on the second visit. Hs-CRP, s-albumin and WBC of the first visit were significantly associated with the progression of IgAGN (P = 0.014; P = 0.0001; P = 0.023, respectively). S-IL-6 was not associated with the progression. All inflammatory variables correlated significantly with the concurrent level of kidney function. Possible study limitations are the relatively low number of outcomes in the study groups, and the lack of generally accepted definitions for disease progression.

CONCLUSIONS

Our results suggest that inflammatory markers hs-CRP, s-albumin and WBC are associated with the progression of IgAGN.