Reduction of diastolic blood pressure: Should hypertension guidelines include a lower threshold target?

Table 3 Meta-analyses and systematic reviews of blood pressure lowering trials

Study	No.	Trials	DBP J-curve Nadir1	Findings	Limitations
2009 Cochrane Database Syst Rev	22089	7	Not observed at 85	In hypertensive patients, lower vs standard BP targets (DBP 85 vs < 90) did not improve mortality or CV events	Difference in mean DBP was 3.4 mmHg between groups. In 2 trials, most did not achieve lower DBP targets. Failure to demonstrate harms with “lower targets” may be due to reporting bias
2011 Ann Intern Med	2272	3	Not observed at 75-80	In patient with CKD, lower BP targets (DBP < 75-80) did not improve renal outcomes	Data on deaths and CV disease outcomes were not informative given the lack of ascertainment or low event rate. Included very few patients with CKD; trial duration may have been too short to detect events
2013 Cochrane Database Syst Rev	2580	4	Not observed at 76	In diabetics, comparing lower vs standard DBP targets, no difference observed in CV mortality or CV events. Lower groups showed trend towards reduced non-cardiac mortality	High risk of selection bias for every outcome analyzed in favor of the “lower” DBP target
2013 CMAJ	9287	11	Not observed at 75-92	In patients with CKD, intensive BP lowering, compared to standard therapy, reduced risk of kidney failure, but not the risk of CV events (CV outcome data available only in 5 of 11 trials)	Did not include patient with diabetes. Heterogeneity of individual study limits the strength of conclusions
2015 Lancet	44989	19	Not observed at 76	In high risk patients, intensive vs standard BP therapy reduced major CV events, including CVA; but more intensive BP lowering no further benefits on mortality	Many trials did not achieve target BP levels in most patients. Mean BP in intensive groups was 133/76
2015 JAMA	100354	40	Not observed at 64-83	In diabetics, BP lowering improved mortality and CV events if baseline SBP > 140, but no outcome benefit if baseline SBP < 140 except CVA and albuminuria	Scarcity of large trials with achieved BP levels of < 70-80 (baseline DBP 70-106)
2016 BMJ	73738	49	78	In diabetics, if SBP < 140, risk of CV mortality increased by 28 percentage points for each 10 mmHg decrease in baseline DBP (P = 0.013)	Most included trials were not designed to evaluate different BP targets, but randomized patients to drugs or placebo

¹mmHg. BP: Blood pressure; CKD: Chronic kidney disease; CV: Cardiovascular; DBP: Diastolic blood pressure.