Risk Factors Associated with Progression in Primary IgA Nephritis to Chronic Renal Failure

 

Risk factors:

(1) arterial hypertension at the time of first renal biopsy (defined as one of the following: (a) systolic blood pressure >= 140 mm Hg, (b) diastolic blood pressure >= 90 mm Hg, or need for antihypertensive therapy)

(2) global optical score (GOS) of Alamartine et al (previous section)

(3) body mass index (BMI) at the time of the first renal biopsy

Risk Factor	Finding	Points
arterial hypertension	absent	0
	present	1
BMI	< 25 kg per square meter	0
	>= 25 kg per square meter	1

 

The global optical score did not have a precise cut-off value.

(1) The relative risk was 1.18 for each point (range in score 0 to 20).

(2) The global score tended to be higher in obese patients.

(3) In the implementation I used a score > 6 as a risk factor. This is unsupported based on the paper (although it does correspond to the mean value for nonobese patients).

(4) Since the relative risk increases with the total score, assigning more points for higher scores (for example, 2 points if over 10) might be necessary.

 

Risk Factor	Relative Risk	95% CI	p value
arterial hypertension	2.90	1.5 to 10.6	0.05
global optical score	1.18	1.0 to 1.4	0.05
BMI	1.10	1.0 to 1.2	0.04
overweight (BMI >= 25)	2.1	0.9 to 4.7	0.09 (NS)

from Table 4, page 725, base don multivariate analysis for CRF-free survival

 

number of risk factors =

= SUM(points for risk factors)

 

Interpretation:

• minimum number of risk factors: 0

• maximum number of risk factors: 3

• The more risk factors that are present, the greater the risk for chronic renal failure.