A Longitudinal Study of the Yield and Clinical Utility of a Specifically Designed Secondary Hypertension Investigation Protocol

Figures & data

Table 1. Medication score based upon relative potencies; a score is given if one of the listed medications is used

Score	Medication
1	Atenolol 25 mg, Nicardipine 15 mg, Labetalol 100 mg
2	Atenolol 50 mg, Hydrochlorothiazide 2.5 mg, Amlodipine 5 mg, Lisinopril 5 mg, Doxazosin 1 mg, Indapamide 2.5 mg
3	Atenolol 75 mg, Nicardipine 45 mg, Labetalol 300 mg
4	Atenolol 100 mg, Amlodipine 10 mg, Lisinopril 15 mg, Losartan 100 mg, Doxazosin 4 mg
5	Doxazosin 8 mg, Lisinopril 20 mg, Amlodipine 20 mg
6	Atenolol 200 mg, Losartan 200 mg, Doxazosin 16 mg

Table 2. Breakdown of patients according to the results of investigations

Result of investigation	Number	Therapeutic interventions
No cause found	77 (81.2%)
Secondary hypertension	18 (18.8%)
Renovascular disease	13 (13.8%)	11 angioplasties in eight patients two surgical repair or RAS one nephrectomy
Parenchymal renal diseasea	1 (1.1%)
Phaeochromocytoma	1 (1.1%)	Adrenalectomy
Miscellaneousb	3 (2.1%)
Hypertension cured	3 (3.2%)	Two cases of renovascular disease (one with angioplasty and one with surgical repair); one adrenalectomy

^aIgA nephropathy.

^bHypothyroidism, Cushing's syndrome, and renal artery aneurysm.

Figure 1. Change in mean daytime systolic and diastolic blood pressure with time, plotted with the change in mean medication score with time. There was a significant decline in systolic and diastolic blood pressure (P<0.001).

Table 3. Diagnostic accuracy of some of the tests employed

Test	Sensitivity (%)	Specificity (%)	Positive predictive value (%)	Negative predictive value (%)
Clinical assessment	18	50	50	83
Urinalysis	59	69	24	85
U and Ea	29	33	28	84
CT scanb	100	96	17	86
Renogram	60	82	38	88

^aElectrolyte and renal function measurement.

^bFigures are calculated for cases of adrenal disease diagnosed.

Table 4. Costings for various elements of secondary hypertension protocol

Variable	Cost (Euro)	Number (%) of patients undergoing test	Contribution to overall costc (%)
Blood testsa	72.0	95 (99%)	4.0
Urine testsb	101.8	95 (99%)	5.3
CT scan	324	90 (94%)	16.8
Renogram	294.8	72 (75%)	12.2
Renal angiogram	508.2	89 (93%)	26.1
Nurse time	190.6	—	10.6
Doctor time (H.O.)	20.3	—	1.1
Doctor time (consultant)	22.1	—	1.2
Day bed charge	419.3	—	23.2

^aBiochemistry, aldosterone, cortisol.

^bCatecholamines, urinalysis.

^cMay not total 100% due to rounding.