Insulin resistance and the progression of IgA glomerulonephritis.
BACKGROUND
IgA glomerulonephritis (IgAGN) has a highly variable prognosis with 15-40% of patients progressing to end-stage renal disease. Hypertension, proteinuria and renal insufficiency are risk factors associated with poor prognosis. The role of insulin resistance is unclear in IgAGN.


METHODS
From a retrospective cohort of IgAGN patients, a total of 174 patients (104 males) were invited for two visits at the clinic, 11 and 16 years (median times) after IgAGN was diagnosed in renal biopsy. Of all the patients, 63% had been diagnosed at least 10 years before the first visit. Progressive disease was defined as cystatin-C exceeding normal limits and showing over 20% elevation between the first and second visits, or kidney transplantation or start of dialysis. Plasma insulin, homeostasis model assessment of insulin resistance (HOMA-IR) index and cystatin-C were obtained for analysis from 118 patients.


RESULTS
IgAGN was progressive in 19.5% of the patients on the second visit. Insulin level and HOMA-IR of the first visit showed significant association with the progression of IgAGN (P = 0.019 and 0.005, respectively).


CONCLUSIONS
Our results show that in addition to the known risk factors age, hypertension, proteinuria and hyperuricaemia, plasma insulin level and calculated HOMA-IR are associated with the progression of IgAGN.
Kaartinen
Kati
K
Department of Internal Medicine, Tampere University Hospital, Tampere, Finland. kati.kaartinen@pp.inet.fi
Syrjänen
Jaana
J
Pörsti
Ilkka
I
Harmoinen
Aimo
A
Pasternack
Amos
A
Huhtala
Heini
H
Niemelä
Onni
O
Mustonen
Jukka
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D005922:Glomerulonephritis, IGA / Q000097:blood* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011480:Protease Inhibitors; D012189:Retrospective Studies
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D007328:Insulin; D011480:Protease Inhibitors