Management of hypertension in patients with diabetes mellitus and metabolic syndrome in Swiss primary care

To the Editor: Although the prevalence of metabolic syndrome (MetS) and diabetes mellitus (DM) is constantly rising in Europe, target blood pressure (TBP) attainments remain low. Although studies show that approximately 29% of hypertensive Swiss Diabetics meet their goals (1), control-rates for patients with MetS remain unknown. DM and MetS have overlapping pathogeneses. However, it remains unclear what additional risk a diagnosis of MetS affords above that of DM only. As a result, no conclusive recommendations exist for patients with MetS. Some guidelines classify MetS patients as at high risk, however, still only recommend starting antihypertensive treatment at a relatively high BP-threshold (140 mmHg) (2). With regards to hypertensive diabetics, the guidelines are more specific, recommending a TBP of <130/80 mmHg (4,5) or TBP <125/75 mmHg in the presence of renal end-organ damage – chronic kidney disease (CKD) or proteinuria >1 g/dl (2). Considering the pathophysiology of DM and MetS, treatment needs to extend beyond mere control of BP. The choice of substances should be metabolically neutral what make compounds interfering with the systemic and cellular RAAS (2) particularly suitable. For DM, the current SSH-guidelines recommend angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) as first-line agents (3). Alternatively, calcium channel-blockers (CCB) or beta-blockers (BB) may be used, whereas diuretics (D) are not recommended. In MetS, ACEIs and ARBs are equivalently recommended as first-line agents (4) and low-dose Ds or CCBs are suitable if TBP cannot be met with monotherapy. Because BBs aggravate insulin resistance (5) (with the exception of carvedilol and nebivolol), they are not recommended as first-line therapy. For this investigation, we collected primary-care data of 4594 hypertensive patients within 1 week (Table 1). Differences in treatment approaches and TBP-attainment were investigated for patients with (i) MetS without DM, (ii) MetS with DM and (iii) DM only. One hundred and sixty three patients qualified to have DM exclusively. Eight hundred and sixty three subjects were diagnosed with MetS (WHO-definition), but without DM, whereas 768 patients showed MetS and DM. Herein, we analysed the most commonly prescribed substance-classes and the influence of single pill combination (SPC) on TBP-attainment in both high-risk-populations. In addition, the impact on TBP-attainment and the appearance of end-organ damage/co-morbidities was compared in patients treated with beta blocker (BB), high dose diuretics (Ds) or with ARB, CCB and ACEI-based therapies. TBP was attained in 25.2% and in 28.7% in patients with DM and MetS (Figure 1). Most often Ds (61%), ARBs (40%) and ACEIs (31%) were prescribed in DM, while Ds (68%), ARBs (48%) and BBs (41%) were used in patients with MetS. Higher BMI was associated with greater SPC-prescription and older patients (>65 years) were more likely to receive dual free combination. Ds were more often used in low-dose formulation compared to high-dose-administration and appeared more frequently used in monotherapy. Patients with MetS were more likely to receive ARBs, ACEIs, CCBs and low-dose Ds than BBs and/or high-dose Ds. However, favourable combinations of RAAS-inhibitors and CCB were used in only 15.6% of diabetics, whereas unfavourable combinations like BB/D were prescribed up to 10.3% in patients with MetS. (A) Blood pressure staging according to SSH (3), TBPA within the subgroups of (B) diabetics (C) patients with MetS. BP, blood pressure; DM, diabetes mellitus; CKD, chronic kidney disease; MetS, metabolic syndrome; TBPA, target blood pressure attainment. Applied TBPA: DM (B) and MetS (C) overall represents the pooled TBPA of all groups within either the diabetic patient population or within patients with MetS, DM with/without microalbuminuria: <140/80 mmHg, DM with CKD: <125/75 mmHg, DM in elderly: <140/90 mmHg, MetS) DM: 140/90 mmHg, MetS + DM: 130/80 mmHg, MetS with CKD: <125/75 mmHg, MetS in elderly: <140/90 mmHg. (A) indicates the distribution of BP-staging in patients with diabetes mellitus and metabolic syndrome, optimal (<120/80 mmHg), normal (120–129/80–84 mmHg), high normal (130–139/85–89 mmHg), stage 1 (140–159/90–99 mmHg), stage 2 (160–179/100–109 mmHg), stage 3 (‡180/‡110 mmHg) Our data indicate that treatment success for both high-risk groups in Switzerland remains poor. Only about 27% of patients in both high-risk groups met blood pressure targets what indicates the necessity for stricter antihypertensive treatment. Given the fact, that the majority of patients had both (DM and MetS) and only a minority was diagnosed with DM alone, guidelines should reflect this emerging group of patients and implement special recommendations. There is an unmet need to define TBP for patients with MetS and to stratify the impact of age, DM and end-organ damages on these goals. Furthermore, the awareness of physicians on unfavourable drugs should be increased to avoid excessive use f Ds (DM: 61%, MetS: 68%) as shown in this investigation. Even though SPC may increase compliance and tolerability, it must not be forgotten that the most common combination partners are Ds, which can worsen insulin sensitivity (6) in both high-risk groups. The original cross-sectional analysis was sponsored by Novartis Pharma, Switzerland. During the time of the survey, HHS was an employee of Novartis Pharms Switzerland. MB and GN were involved in setting up the survey. HHS, JDdV and IS did the sub-analysis and wrote the manuscript. G-R.T did the statistical analysis and was involved in interpretation of the results.