We are far from achieving blood pressure goals in diabetes: Do we really want to do it?

Diabetes is an emerging worldwide problem whose prevalence is expected to grow up. Microvascular and macrovascular complications have a great impact on quality of life and survival of patients and represent an economic and social burden. Current guidelines, regarding the blood pressure (BP) target in diabetic patients, point out the importance of a good BP control in order to prevent cardiovascular and renal complications. The 2013 European Society of Hypertension/European Society of Cardiology (ESH/ESC) Task Force stopped recommending the target of <130/80 mm Hg in patients with diabetes and recommended a goal of <140/85 mm Hg1 in partial accordance with that (<140/90 mm Hg) suggested by Eighth Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High BP (JNC 8).2 Nevertheless, the latest 2018 Canadian hypertension guideline and 2017 American College of Cardiology/American Heart Association (ACC/AHA) guideline have both recommended that adults with diabetes be treated to attain <130/80 mm Hg.3, 4

Recent studies show an alarming failure to achieve both glycemic and BP targets in a real‐life scenario. In this issue of the Journal of Clinical Hypertension, the cross‐sectional study by Yu‐Qing Zhang and colleagues provides information on achievement in BP control in a cohort of 24 512 Chinese patients with type 2 diabetes in a real‐world setting.5 The CCMR‐3B STUDY is an observational, cross‐sectional, multicenter, and multispecialty study of diabetic outpatients conducted in 104 hospitals across major geographic regions in China. Only a minor proportion of this population reached the target BP values of 130/80 mm Hg (28.4%) recommended by Chinese diabetes guidelines. Among patients with hypertension (n = 15 211), 17.5% (n = 2658) achieved the recommended target BP, and 52.2% (n = 7936) had their BP controlled to <140/90 mm Hg. Interestingly, rural area and comorbidities such as obesity, hypertension, and chronic kidney disease (CKD) were associated with a lower goal of optimal BP.

These data are in agreement with a recent nationwide report of the burden of hypertension across all 31 provinces in mainland China6 describing as among the 105 379 subjects with diabetes, a 66% showed hypertension (BP levels above 140/90 mm Hg or antihypertensive treatment) and most were either not treated or treated inadequately. Taken together, these findings show that in China, despite the high prevalence of hypertension, awareness, treatment, and control are low across all population subgroups. Notably, only 182 patients (1.20% among the hypertensive subjects) of the paper to which this commentary is devoted5 were treated with three or more antihypertensive drugs, including a diuretic and therefore defined patients with resistant hypertension. This figure is very different from that described from the AMD study group who in a large, real‐life cohort study in patients with type 2 diabetes and hypertension in Italy, from a total of 29 923 patients with normal baseline estimated glomerular filtration rate (eGFR)7 and of 2778 with stage 3 CKD,8 described a prevalence of 17% and 33% of resistant hypertension, respectively. This discrepancy is at least in part explained, as assessed by the authors, by the very low proportion of patients (2.7%) who are treated with more than two antihypertensive drugs in China.6

Authors’ conclusions point out the need of a more strict BP control and a more aggressive effort to maintain BP target below the recommended value of 130/80 mm Hg. These results are interesting but deserve some comments about the importance of tailoring ideal BP target according to the characteristic of single patient, rather than choosing a standardized, intensive approach toward the lowest possible BP target.

Results from a recent report conducted by AMD study group on a very large diabetic Italian cohort are in line with observations summarized above. In the studied cohort of 116 777 outpatients, 70% (n = 81 750) were hypertensive and 64% of these (n = 52 320) were treated.9 Only about one out of two patients resulted on target when either ADA (<140/80 mm Hg)10 or ESH‐ESC (<140/85 mm Hg)1 recommendations were considered, a percentage that dropped dramatically to about 13% when a more stringent value according to KDIGO guidelines (<130/80 mm Hg) was adopted in the subgroup of patients with high albuminuria. Once again, like in the Chinese study, kidney dysfunction emerges as an independent predictor of failure to achieve therapeutic target levels.

This difficulty in translating ideal BP into clinical practice goes together with recent controversies over the definition of the most appropriate BP target in the individual patient. In fact, while two important meta‐analyses confirm that the lower BP target, the better cardiovascular and renal protection even in patients with diabetes,11, 12 other studies and real‐life data show that below 130 mm Hg risks tend to overcome benefit, except for cerebrovascular events.7, 13 Moreover, a recent meta‐analyses on 16 RCTs on 24 444 diabetic patients concluded that intensive BP lowering treatment had no clear effect on non‐CV death, heart failure or end‐stage kidney disease. According to these latest observations of the existence of a J curve between BP reduction and morbidity, recent guidelines have proposed for the first time a BP value below which is not recommended to maintain BP14 that is 120 mm Hg except for CKD patients that are suggested to be maintained above 130 mm Hg. Although, both in the SPRINT and in the ACCORD sub‐studies,15, 16 the biomarkers of tubule injury investigated suggest that reductions in eGFR that occur during intensive BP lowering may largely reflect hemodynamic effects rather than kidney injury, the significance of the finding that a more intensive BP control appears to acutely lower eGFR remains uncertain. Less residual kidney function may make participants with CKD particularly vulnerable to additional damage, resulting in loss of kidney function. As a matter of fact, in a pooled analysis of the AASK and MDRD trials, acute eGFR declines ≥20% during intensive BP lowering identified a subset of patients at higher risk for adverse outcomes.17

The occurrence of benefits (ie, renal protection in subjects with proteinuria, reduced cardiovascular disease, and improved survival) concurrent with some adverse events (ranging from incident AKI, eGFR decline >30%, hypokalemia, hyponatremia, and hypotension) highlights the importance of shared decision‐making when clinicians propose an intensive BP goal to their patients. Taken together, these observations indicate a large area of potential therapeutic improvement that could optimize cardiovascular risk profile and therefore prevent further micro‐ and macrovascular complications. Moreover, both Chinese and Italian databases suggest that impairment of renal function may hamper the effectiveness of antihypertensive treatment and emphasize the importance of taking into account both results from studies and data from real life in order to considering in clinical practice a treatment approach tailored on the characteristics and risk profile of single patient. Future research should be planned bearing in mind that BP targets in fragile patient subgroups need to be better identified.

CONFLICT OF INTEREST

None declared.