Association between the progression of immunoglobulin A nephropathy and a controlled status of hypertension in the first year after diagnosis

BACKGROUND/AIMS: Hypertension is considered a risk factor in immunoglobulin A nephropathy (IgAN). However, after IgAN diagnosis, the relationship between early blood pressure control and renal prognosis remains unclear. This study aimed to analyze the association between the prognosis of IgAN patients and a controlled status of hypertension within the first year of IgAN diagnosis. METHODS: We retrospectively analyzed 2,945 patients diagnosed with IgAN by renal biopsy. The patients were divided into 'normal,' 'new-onset,' 'well-controlled,' and 'poorly-controlled' groups using blood pressure data from two consecutive measurements performed within a year. The Kaplan-Meier survival analysis and Cox proportional-hazards regression model were used to survey the independent association between recovery from hypertension and the risk of IgAN progression. The primary endpoint was IgAN progression defined as the initiation of dialysis or kidney transplantation. RESULTS: Before IgAN diagnosis, 1,239 patients (42.1%) had been diagnosed with hypertension. In the fully adjusted Cox proportional-hazards models, the risk of IgAN progression increased by approximately 1.7-fold for the prevalence of hypertension. In the subgroup analyses, the 'well-controlled' group showed a statistically significant risk of IgAN progression (hazard ratio [HR], 3.19; 95% confidence interval [CI], 1.103 to 9.245; p = 0.032). Moreover, the 'new-onset' and 'poorly-controlled' groups had an increased risk of IgAN progression compared to the 'normal' group (HR, 2.58; 95% CI, 1.016 to 6.545; p = 0.046 and HR, 3.85;95% CI, 1.541 to 9.603; p = 0.004, respectively). CONCLUSION: Although hypertension was well-controlled in the first year after IgAN diagnosis, it remained a risk factor for IgAN progression.