The evidence for alcohol interventions to reduce BP
Several systematic reviews and meta-analyses have shown that alcohol consumption and hypertension are linked in a dose-dependent fashion [
20‐
23], although there may be a threshold level for alcohol consumption below which there are no effects, especially for women [
24,
25] (for indirect evidence see [
26]). As indicated by the potential threshold, the dose-response relationship is not linear over the full range of alcohol consumption, but for both sexes there is a monotonic dose-response relationship for higher levels of consumption [
20,
22,
24], and thus hazardous/harmful drinking and AUDs are closely associated with elevated BP and/or hypertension [
23,
27,
28]. The above described association between hazardous/harmful alcohol consumption and hypertension has been judged as causal [
29‐
31], which means that a logical intervention to reduce BP is to reduce alcohol consumption.
Indeed, several studies support the efficacy and effectiveness of interventions to decrease alcohol consumption in reducing BP levels, with a clinically meaningful decline in BP occurring within a few weeks after reductions in alcohol intake among hypertensive patients [
30,
32,
33]. The most comprehensive systematic review and meta-analyses on the effect of alcohol consumption on BP in trials lasting at least 7 days (median duration: 4 weeks) found that, above a baseline drinking level of two drinks per day (drink size was assumed to be 12 g pure alcohol), reduction in alcohol intake was associated with BP reduction [
34]. The higher the alcohol consumption at baseline, the greater the reduction in alcohol consumption and in BP levels. The effect could also be shown for people with hypertension [
34]. The evidence supporting this intervention is of the highest possible grade [
35], as it is based on a systematic review and meta-analyses of randomized controlled trials of interventions to reduce BP in both normotensives and hypertensives, with adequate control groups (for the importance of control groups specifically in the area of interventions for lowering BP see the paper by Patel et al. [
36]).
The available evidence has led to standard formulations in European and Canadian guidelines for the management of hypertension in the past decades to address lifestyle factors, including alcohol [
37,
38]. In fact, most guidelines, including those from the NICE, stipulate that all patients undergoing assessment or treatment for hypertension should receive initial and periodic lifestyle advice, which includes ascertaining their alcohol consumption and encouraging a reduced intake if they drink hazardously [
39].
The situation in the US is slightly different. Although American Society of Hypertension Community Guidelines briefly mention the contribution of alcohol to raised BP [
40], the association between alcohol consumption and raised BP is not even mentioned in the main national hypertension guidelines [
41] or in the American College of Cardiology/American Heart Association Guidelines regarding lifestyle management to reduce cardiovascular risk [
42].
Interventions to reduce alcohol consumption
In the primary care settings, there is significant overlap of hazardous drinking/AUDs (for background see [
43]) and hypertension. European evidence suggests that 20.6% of hypertensive men aged 40–65 years have an AUD and 16.7% have alcohol dependence. For hypertensive women aged 40–65 years, it is estimated that 7.2% have an AUD and 5.8% have alcohol dependence [
12]. Adding these people to those who do not qualify for an AUD diagnosis but drink above 60 g or 40 g of pure alcohol per day (for men and women, respectively), resulted in 30.9% or 20.0% of men and women aged 40–65 years, respectively, qualifying for alcohol interventions with hypertension. Compared to those without any AUD, patients with an AUD are estimated to have a 1.5- to 5-fold increased risk of hypertension, with the highest risks for hypertension involving higher levels of alcohol consumption [
44‐
46]. In the above-cited study of more than 13,000 patients in primary healthcare [
28,
47], the age-adjusted odds ratio (OR) for hypertension in the age group 40–64 years was 1.59 among those diagnosed with AUD by the treating general practitioner (95% CI 1.35–1.88,
P < 0.001; own calculations – see Additional file
2: Appendix 2) [
47‐
49].
Looking at the odds from hypertension in the cited study, the age-adjusted OR for an AUD was, of course, similar (OR 1.60, 95% CI 1.35–1.88,
P < 0.001) because of the symmetry property of OR, and the odds of qualifying for an intervention among people with hypertension was 1.35 (95% CI 1.12–1.58,
P < 0.001; own calculations; for a description of the study see [
47‐
49]).
Since a reduction in alcohol consumption leads to a decline in BP levels [
32,
34], the question becomes whether effective interventions to reduce alcohol consumption are available in primary healthcare. There is ample evidence, based on randomized controlled trials in many countries, that screening and brief advice are effective in reducing alcohol consumption in hazardous and harmful drinkers [
50], and that effective psychotherapies and pharmacotherapy plus psychosocial interventions are effective in reducing consumption levels in dependent drinkers [
51‐
55]. Despite this evidence, and its inclusion in some guidelines [
37,
39], interventions to reduce alcohol consumption do not play a major role in the management of hypertension at the primary healthcare level in many European countries [
16,
56]. One example that illustrates the paucity of activity in primary healthcare is the recent five-country Optimizing Delivery of Health Care Interventions study that recruited 120 primary healthcare units from Catalonia, England, Netherlands, Poland, and Sweden [
57]. During the 4-week baseline measurement period, in only 1202 out of 179,954 adult consultations (0.67%) were patients screened for and advised about their hazardous drinking.
Studies have identified a number of potential barriers to the adoption of screening and brief advice in primary healthcare, including the lack of resources, training and support from management, as well as workload [
58,
59]. Given this situation, experts in several countries have started to take steps towards better integration of alcohol interventions in primary healthcare [
10‐
14]. Despite obvious differences between healthcare systems, there are clear commonalities in the recommendations made by the different sets of national experts. These recommendations focus on providing incentives for screening and treatment, better education for primary healthcare providers regarding the link between alcohol and hypertension, and the inclusion of simple alcohol tools in electronic patient records, such that the management of alcohol use becomes standard practice for all patients with hypertension.
The potential in Europe – examples from five countries
While control and management of hypertension is a key element of any European guideline for primary healthcare, most general population surveys show that a large minority of women and the majority of men with hypertension aged 40 to 64 either do not know about their health condition or are not adequately controlled (i.e., they show BP values ≥ 140/90 mm Hg; see Table
1 for details).
Table 1
Proportion with hypertension with or without control in large population surveys among 40–64 year olds
France | 30.4% | 46.2% | 64.0% | 36.1% | 2006–2007 |
Germany | 29.6% | 36.5% | 56.0% | 40.1% | 2008–2011 |
Italy | 33.2% | 42.1% | 52.0% | 40.4% | 2008–2012 |
Spain | 30.0% | 42.0% | 62.0% | 48.1% | 2008–2010 |
UK | 22.6% | 27.2% | 31.2% | 23.9% | 2006 |
The following models the joint effects of two interventions (see Additional file
2: Appendix 2). First, it is assumed that 50% of the people aged 40–64 years with uncontrolled hypertension (i.e., BP ≥ 140/90 mm Hg [
37,
60,
61]) receive an intervention (in part but not limited to pharmacotherapy [
37]), which lowers their BP level to that of people with controlled hypertension. Secondly, it is assumed that, among those with uncontrolled hypertension who are receiving hypertension interventions, 50% of those eligible will also receive either brief advice or a brief intervention for hazardous or harmful alcohol use, or treatment for alcohol dependence. The results are summarized in Table
2.
Table 2
Blood pressure indicators among people with hypertension before and after the interventions among people with hypertension, 40–64 years old
France | W | 140.7 | 138.1 | 2.5 | 48% | 41% | 7% | 2.0% |
M | 146.3 | 141.0 | 5.3 | 59% | 48% | 11% | 5.3% |
Germany | W | 141.5 | 138.5 | 3.0 | 49% | 42% | 7% | 2.0% |
M | 143.9 | 139.8 | 4.2 | 55% | 45% | 9% | 3.4% |
Italy | W | 144.7 | 142.1 | 2.6 | 56% | 51% | 6% | 1.8% |
M | 144.2 | 139.7 | 4.4 | 55% | 45% | 10% | 4.0% |
Spain | W | 146.0 | 144.6 | 1.4 | 60% | 57% | 3% | 1.0% |
M | 146.8 | 144.9 | 1.9 | 62% | 57% | 4% | 1.8% |
UK | W | 141.5 | 139.5 | 2.0 | 50% | 45% | 5% | 1.1% |
M | 145.4 | 142.8 | 2.5 | 58% | 52% | 5% | 1.5% |
In each of the countries, the proposed intervention would have a sizeable effect on improving BP levels among 40- to 65-year-old hypertensives and would markedly increase the proportion of people below the threshold 140/90 mm Hg in the general population (for men, between 1.5% and 5.3%; for women, between 1.0% and 2.0%). Both effects are more pronounced in men, which is not surprising, as men have worse control of BP in all countries and, relatedly, they have worse alcohol consumption habits [
1] (Table
2).
The next set of calculations measures the impact of the proposed interventions on mortality and burden of disease as measured in disability-adjusted live years (DALYs) in the same age group within 1 year, using the methodology of comparative risk assessment [
62,
63] (see Additional file
2: Appendix 2). This limitation for 1 year is consistent with knowledge that brief intervention effects will show some attrition over time [
64].
The potential effect of the interventions on reducing mortality would be sizeable. In each of the five countries examined, the reductions of BP and the effects of reduced alcohol would lead to hundreds of deaths avoided within 1 year (Table
3); for instance, in Germany alone, a reduction of 1536 cardiovascular disease deaths, 138 gastrointestinal deaths, and 20 injury deaths. In terms of burden of disease, for Germany, about 86,000 years of life lost due to cardiovascular premature mortality or due to disability in this age group could be avoided, plus another 5500 due to gastrointestinal disease and 3000 due to injury.
Table 3
Lives saved and disability-adjusted life years avoided in major disease categories within 12 months attributable to the interventions among people with hypertension, 40–64 years old
France | W | 111 | 25 | 47 | 12 | 11 | 3 |
| M | 1041 | 443 | 276 | 109 | 88 | 30 |
Germany | W | 275 | 83 | 98 | 25 | 22 | 2 |
| M | 1261 | 633 | 246 | 113 | 100 | 18 |
Italy | W | 158 | 42 | 57 | 10 | 9 | 1 |
| M | 805 | 389 | 180 | 98 | 82 | 15 |
Spain | W | 50 | 16 | 22 | 4 | 3 | 1 |
| M | 301 | 164 | 76 | 48 | 38 | 8 |
UK | W | 77 | 27 | 29 | 25 | 24 | 2 |
| M | 378 | 220 | 78 | 84 | 75 | 11 |
DALYs | | | | | | | |
France | W | 10,590 | 2850 | 5189 | 456 | 417 | 418 |
| M | 56,844 | 23,237 | 19,335 | 4235 | 3710 | 2914 |
Germany | W | 21,179 | 7042 | 8703 | 1007 | 943 | 599 |
| M | 64,840 | 31,245 | 16,983 | 4491 | 4022 | 2379 |
Italy | W | 15,543 | 4948 | 5872 | 489 | 452 | 536 |
| M | 47,273 | 21,992 | 13,020 | 4305 | 3777 | 2491 |
Spain | W | 4764 | 1483 | 2100 | 181 | 159 | 233 |
| M | 16,419 | 8086 | 5007 | 1934 | 1660 | 1198 |
UK | W | 4860 | 1648 | 2117 | 1012 | 936 | 495 |
| M | 18,354 | 9581 | 5348 | 3394 | 3033 | 1632 |
This does not even include the effect of reduced alcohol use on other disease categories such as AUDs or cancer. For the latter disease category, the effects would only be seen after decades due to the long time lag [
65]. For the other disease categories, lag times are short [
66], and the vast majority of deaths will be covered, including liver cirrhosis deaths, where interventions have shown immediate effects [
67].