Fig. 4: Predictors of clinical outcome from surgery.

a–d, Influence of age (a), sex (b), baseline SBP (c) and ethnicity (d) on clinical outcomes. As seen from a and b, age and female sex are associated with a higher likelihood of complete clinical success. For age treated as categorical groups, statistical significance was determined by Fisher’s exact test (P = 0.065). For age treated as continuous, in univariate proportional odds logistical regression, the odds ratio was 0.43 (95% CI = 0.27 to 0.67) for an improvement of one level of outcome per 10 years of age (P = 0.00022). For sex, statistical significance was determined by Fisher’s exact test (P = 0.000036). For female versus male in a univariate proportional odds model, the odds ratio of going up one level of outcome was 9.078 (95% CI = 3.07 to 26.81) (P = 0.000065). n = 78. In c, the baseline SBP was lower in patients achieving complete or absent clinical success than in those achieving partial success. Each dot represents a single patient and is color coded to indicate the individual’s ethnicity. The center line of the box represents the median, the upper and lower boundaries of the box represent the interquartile range and the upper and lower whiskers represent the maximum and minimum values in the range, respectively. n = 78. For d, the absence of clinical success (shown in blue) was significantly more frequent in patients who were Black compared with other ethnicities. In a univariate proportional odds model, the odds ratio of going up one level was 0.14 (95% CI = 0.042 to 0.49). Statistical significance was determined by two-sided t-test (P = 0.002). e, Correlation between the decrease in SBP after 4 weeks of spironolactone therapy and the decrease in SBP at 6 months post-surgery (r = 0.53 (95% CI = 0.32 to 0.69) and P = 0.000012). The P value comes from a correlation test whose test statistic follows a t distribution. SBP is shown as an adjusted percentage change, which was calculated with Oldham’s correction¹⁶ (corrected change in blood pressure (%) = 100× the actual change in blood pressure divided by the average of the baseline and post-treatment pressure). n = 67. f, SBP after 4 weeks of spironolactone predicts clinical success. All patients whose SBP dropped to ≤135 mmHg after 4 weeks of spironolactone achieved either partial or complete clinical success. SBP ≤ 135 mmHg after 1 month of spironolactone was the best univariate predictor of complete clinical success with an odds ratio of 13.0 (3.72 to 45.24). Statistical significance was determined by two-sided t-test (P = 0.000057). n = 67.