IgA nephropathy – how do patients with mild disease do?

I see several patients each year with mild urinary abnormalities – microscopic hematuria, sub-nephrotic albuminuria and normal renal function. What should one do with these patients? Truthfully, what I do is recommend fish oil, angiotensin blockade and a strategy of aggressively managing the blood pressure. In patients with mild renal insufficiency (Scr ≈1.5 mg/dL) I tend to treat the patient with steroids. But what if I decided not to treat this patient? How would they do?

A study by Guteirrz and colleagues in JASN, in the current issue, provides insights from long-term follow up in patients with biopsy proven IgA nephropathy with minimal urinary abnormalities. These investigators followed 141 Caucasian patients at 8 Spanish centers with biopsy proven IgA nephropathy with minor urinary abnormalites. Mean age was 23.7 years, nearly 64% were male, mean serum creatinine was 0.8 mg/dL. The mean proteinuria was 0.2 g/day, 100% had microhematuria. Median follow-up was for 108 months (yes that’s over 9 years!). 32% had mesangial proliferation on renal biopsy. No patient received immunosuppressants, corticosteroids or fish oil. Nearly 42% of patuients received an angiotensin blocker.

The results are striking:

• Only 3.5% of patients had a >50% increase in serum creatinine; doubling of serum creatinine in only 1 of 141 patients. No patients developed ESRD.
• Proteinuria of >0.5 g/24h developed in only ≈15% of patients. At the end of follow-up median proteinuria was 0.1 g/24 h (0.0-0.4 g/24h) and 29% of patients had negative proteinuria.
• Hypertension was present at baseline in ≈16% and  in ≈21% at the end of follow-up.

The conclusions were:

• Long-term outcome in patients with IgA nephropathy with normal kidney function and minimal or negative proteinuria is not a progressive disease, at least in Caucasian patients.
• Approximately 37.5% of patient’s had a clinical remission (defined as dissapearance of microhematuria and proteinuria (<0.2 g/24h) with normal renal function and normal blood pressure. Patients who remitted tended to have lower proteinuria and were non-smokers at presentation.