Description of studies
The study selection process is detailed in a flow chart as per PRISMA
guidelines (Figure 1). The initial MEDLINE search returned 191 results,
Embase 384 and Central 564 (1139 in total). After removal of duplicates
there were 967 articles of which 769 were excluded based on title and
abstract. The remaining 198 full-text articles were assessed for
eligibility and 153 were excluded for various reasons (Figure 1). The
remaining 45 articles were included in the qualitative synthesis. MRA
and potassium-sparing diuretics were grouped together for the analysis
as only one study had measurements for a potassium-sparing diuretic
(amiloride) with the remainder MRAs. The most commonly used diuretic
class was the MRA/potassium-sparing class. Classes of diuretic were
thiazide/thiazide-like (24/45, 53%), MRA/potassium-sparing (28/45,
62%), loop (4/45, 9%) and combination (3/45, 7%). Individual
diuretics were hydrochlorothiazide, amiloride, indapamide,
bendroflumethiazide, chlorthalidone, canrenone, furosemide,
spironolactone, eplerenone, tielinic acid and torsemide. Details of
individual trials are summarised in table 1. In those studies where
patients where previously treated with another antihypertensive
medication before the diuretic was added, an ACE/ARB was included in
over 50%. For renin sub-analysis, plasma renin activity (PRA) was used
as this was the most common measure of renin in the studies.