Table 2.
Clinical characteristics of patients stratified by histopathologic findings of classical and nonclassical unilateral primary aldosteronism
| Variable | N | Total Cohort (n = 36) | Classical (n = 24) | Nonclassical (n = 12) | P-value |
|---|---|---|---|---|---|
| Age at surgery (years) | 36 | 49 (13.4) | 49 (13.6) | 49 (13.6) | 0.959 |
| Sex (ref. female) | 36 | 20 (55.6) | 13 (54.2) | 7 (58.3) | 0.813a |
| Body mass index (kg/m2) | 36 | 26.7 (4.83) | 26.5 (4.51) | 27.0 (5.62) | 0.800 |
| Known duration of HTN (months) | 35 | 50 (4-134) | 11 (3-100) | 114 (48-176) | 0.010 |
| Genotype: KCNJ5 mutated | 29 | 12 (41.4) | 11 (50.0) | 1 (14.3) | 0.187 |
| Largest nodule size at pathology (diameter, mm) | 30 | 9 (7-18) | 12 (8-20) | 6 (3-10) | 0.019 |
| Clinical parameters at baseline | |||||
| Plasma aldosterone (pmol/L) | 36 | 627 (457-870) | 659 (457-922) | 567 (409-754) | 0.518 |
| DRC (mU/L) | 36 | 3.3 (2.0-7.1) | 2.2 (2.0-7.1) | 4.4 (2.0-13.8) | 0.416 |
| ARR ([pmol/L]/[mU/L]) | 36 | 162 (71-356) | 170 (82-356) | 139 (41-355) | 0.476 |
| Lowest serum potassium (mmol/L) | 36 | 3.1 (0.52) | 3.0 (0.43) | 3.4 (0.62) | 0.031 |
| Systolic BP (mmHg) | 36 | 147 (21.4) | 148 (24.1) | 147 (15.7) | 0.927 |
| Diastolic BP (mmHg) | 36 | 92 (18.1) | 92 (19.8) | 93 (14.8) | 0.853 |
| AntiHTN medication (defined daily dose) | 36 | 2.13 (1.00-3.88) | 2.38 (1.13-3.88) | 2.00 (0.81-3.75) | 0.608 |
| Lateralization index | 33 | 12.9 (5.1-27.2) | 13.9 (6.7-36.2) | 5.8 (4.4-11.5) | 0.048 |
| Clinical parameters at follow-up | |||||
| Plasma aldosterone (pmol/L) | 34 | 323 (183-584) | 276 (155-494) | 473 (240-1086) | 0.058 |
| DRC (mU/L) | 34 | 14.5 (6.6-25.4) | 17.0 (9.2-28.9) | 6.5 (4.4-18.4) | 0.044 |
| ARR ([pmol/L]/[mU/L]) | 34 | 28 (8-52) | 21 (6-32) | 48 (28-115) | 0.006 |
| Lowest serum potassium (mmol/L) | 34 | 4.2 (0.46) | 4.4 (0.41) | 3.9 (0.42) | 0.006 |
| Systolic BP (mmHg) | 34 | 136 (16.2) | 134 (17.2) | 140 (14.0) | 0.338 |
| Diastolic BP (mmHg) | 34 | 87 (12.6) | 86 (14.2) | 88 (9.5) | 0.758 |
| Anti-HTN medication (defined daily dose) | 34 | 0.83 (0.00-2.13) | 0.58 (0.00-2.53) | 1.00 (0.50-1.88) | 0.423 |
| Clinical Outcome | |||||
| Complete | 34 | 4 (11.8) | 4 (18.2) | 0 (0.0) | 0.286 |
| Partial | 22 (64.7) | 13 (59.1) | 9 (75.0) | ||
| Absent | 8 (23.5) | 5 (22.7) | 3 (25.0) | ||
| Biochemical Outcome | |||||
| Complete | 34 | 22 (64.8) | 18 (81.9) | 4 (33.3) | 0.008 b |
| Partial | 6 (17.6) | 3 (13.6) | 3 (25.0) | 0.641b | |
| Absent | 6 (17.6) | 1 (4.5) | 5 (41.7) | 0.014 b |
Unadjusted analysis of clinical parameters with data shown as the mean (SD), n (%), or median (IQR). P-values less than 0.05 were considered significant. Patient data from all cases of agreement between pathologists (36 of 37 resected adrenals with 25 cases of agreement between group 1 pathologists and 11 cases of agreement between group 2 pathologists (Fig. 2). The remaining patient with disagreement between pathologists was excluded from the analysis.
Classical, indicates “classical” histopathology associated with unilateral PA of a solitary APA or aldosterone-producing nodules; nonclassical, indicates “nonclassical” histopathology of multiple aldosterone-producing micronodules or multiple aldosterone-producing nodules (or multiple aldosterone-producing micronodules and multiple aldosterone-producing nodules together) or aldosterone-producing diffuse hyperplasia. Adrenal nodule diameter refers to the size of the largest nodule measured at pathology; lowest serum potassium refers to the lowest recorded serum potassium ion concentration and antihypertension medication is expressed as defined daily dose, which is the assumed average maintenance dose per day for a drug used for its main indication in adults (ATC/DDD Index 2010). The catheterization of the right adrenal gland was unsuccessful for 3 of 36 patients (lateralization indices could not be calculated). Follow-up measurements were unavailable for 2 of the 36 patients. Pairwise differences are shown for biochemical outcomes which displayed an overall group difference (P = 0.017). Genotype data was available for 29 of the 36 patients: a KCNJ5 mutation positive group (n = 12), and a KCNJ5 mutation negative group (n = 17). The latter group comprised those with no mutation detected (n = 13), ATP1A1 mutations (n = 2), a CACNA1D mutation, and a PRKACA mutation. Clinical and biochemical outcomes after unilateral adrenalectomy were assessed in accordance with the PASO criteria at 6 to 12 months after surgery (24).
Abbreviations: ARR, aldosterone-to-renin ratio; BMI, body mass index; BP, blood pressure; DRC direct renin concentration; HTN, hypertension; KCNJ5, potassium inwardly rectifying channel subfamily J member 5; ref., reference.
a P-value is for sex in general.
bOverall P-value for biochemical outcomes = 0.009.