Most medical researchers, whether clinical or non-clinical, receive some background in statistics as undergraduates. However, it is most often brief, a long time ago, and largely forgotten by the time it is needed. Furthermore, many introductory texts fall short of adequately explaining the underlying concepts of statistics, and often are divorced from the reality of conducting and assessing medical research.

Practical Statistics for Medical Research is a problem-based text for medical researchers, medical students, and others in the medical arena who need to use statistics but have no specialized mathematics background. 

The author draws on twenty years of experience as a consulting medical statistician to provide clear explanations to key statistical concepts, with a firm emphasis on practical aspects of designing and analyzing medical research. The text gives special attention to the presentation and interpretation of results and the many real problems that arise in medical research

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Practical statistics for medical research

2007 Guidelines for the Management of Arterial Hypertension : The Task Force for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC).

Because of new evidence on several diagnostic and therapeutic aspects of hypertension, the present guidelines differ in many respects from the previous ones. Some of the most important differences are listed below: 
1. Epidemiological data on hypertension and BP control in Europe. 
2. Strengthening of the prognostic value of home blood pressure monitoring (HBPM) and of its role for diagnosis and management of hypertension, next to ambulatory blood pressure monitoring (ABPM). 
3. Update of the prognostic significance of night-time BP, white-coat hypertension and masked hypertension. 
4. Re-emphasis on integration of BP, cardiovascular (CV) risk factors, asymptomatic organ damage (OD) and clinical complications for total CV risk assessment. 
5. Update of the prognostic significance of asymptomatic OD, including heart, blood vessels, kidney, eye and brain. 
6. Reconsideration of the risk of overweight and target body mass index (BMI) in hypertension. 
7. Hypertension in young people. 
8. Initiation of antihypertensive treatment. More evidence-based criteria and no drug treatment of high normal BP. 
9. Target BP for treatment. More evidence-based criteria and unified target systolic blood pressure (SBP) (<140 mmHg) in both higher and lower CV risk patients. 
10. Liberal approach to initial monotherapy, without any all-ranking purpose. 
11. Revised schema for priorital two-drug combinations. 
12. New therapeutic algorithms for achieving target BP. 
13. Extended section on therapeutic strategies in special conditions. 
14. Revised recommendations on treatment of hypertension in the elderly. 
15. Drug treatment of octogenarians. 
16. Special attention to resistant hypertension and new treatment approaches. 
17. Increased attention to OD-guided therapy. 
18. New approaches to chronic management of hypertensive disease

/pdf/2013-esh-esc-guidelines-for-the-management-of-arterial-4eubk4p0u3.pdf

2013 ESH/ESC Guidelines for the management of arterial hypertension: the Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC)

Abstract Objective: To determine the effects of “prolonged” antiplatelet therapy (that is, given for one month or more) on “vascular events” (non-fatal myocardial infarctions, non-fatal strokes, or vascular deaths) in various categories of patients. Design: Overviews of 145 randomised trials of “prolonged” antiplatelet therapy versus control and 29 randomised comparisons between such antiplatelet regimens. Setting: Randomised trials that could have been available by March 1990. Subjects: Trials of antiplatelet therapy versus control included about 70 000 “high risk” patients (that is, with some vascular disease or other condition implying an increased risk of occlusive vascular disease) and 30 000 “low risk” subjects from the general population. Direct comparisons of different antiplatelet regimens involved about 10 000 high risk patients. Results: In each of four main high risk categories of patients antiplatelet therapy was definitely protective. The percentages of patients suffering a vascular event among those allocated antiplatelet therapy versus appropriately adjusted control percentages (and mean scheduled treatment durations and net absolute benefits) were: (a) among about 20 000 patients with acute myocardial infarction, 10% antiplatelet therapy v 14% control (one month benefit about 40 vascular events avoided per 1000 patients treated (2P< 0.00001)); (b) among about 20 000 patients with a past history of myocardial infarction, 13% antiplatelet therapy v 17% control (two year benefit about 40/1000 (2P<0.00001)); (c) among about 10 000 patients with a past history of stroke or transient ischaemic attack, 18% antiplatelet therapy v 22% control (three year benefit about 40/1000 (2P<0.00001)); (d) among about 20 000 patients with some other relevant medical history (unstable angina, stable angina, vascular surgery, angioplasty, atrial fibrillation, valvular disease, peripheral vascular disease, etc), 9% v 14% in 4000 patients with unstable angina (six month benefit about 50/1000 (2P<0.00001)) and 6% v 8% in 16 000 other high risk patients (one year benefit about 20/1000 (2P<0.00001)). Reductions in vascular events were about one quarter in each of these four main categories and were separately statistically significant in middle age and old age, in men and women, in hypertensive and normotensive patients, and in diabetic and non: diabetic patients. Taking all high risk patients together showed reductions of about one third in non-fatal myocardial infarction, about one third in non-fatal stroke, and about one sixth in vascular death (each 2P<0.00001). There was no evidence that non-vascular deaths were increased, so in each of the four main high risk categories overall mortality was significantly reduced. The most widely tested antiplatelet regimen was “medium dose” (75-325 mg/day) aspirin. Doses throughout this range seemed similarly effective (although in an acute emergency it might be prudent to use an initial dose of 160-325 mg rather than about 75 mg). There was no appreciable evidence that either a higher aspirin dose or any other antiplatelet regimen was more effective than medium dose aspirin in preventing vascular events. The optimal duration of treatment for patients with a past history of myocardial infarction, stroke, or transient ischaemic attack could not be determined directly because most trials lasted only one, two, or three years (average about two years). Nevertheless, there was significant (2P<0.00001) further benefit between the end of year 1 and the end of year 3, suggesting that longer treatment might well be more effective. Among low risk recipients of “primary prevention” a significant reduction of one third in non: fatal myocardial infarction was, however, accompanied by a non-significant increase in stroke. Furthermore, the absolute reduction in vascular events was much smaller than for high risk patients despite a much longer treatment period (4.4% antiplatelet therapy v 4.8% control; five year benefit only about four per 1000 patients treated) and was not significant (2P=0.09). Conclusions: Among a much wider range of patients at high risk of occlusive vascular disease than is currently treated routinely, some years of antiplatelet therapy - with aspirin 75-325 mg/day or some other antiplatelet regimen (provided there are no contraindications) - offers worthwhile protection against myocardial infarction, stroke, and death. Significant benefit is evident not only among patients with unstable angina, suspected acute myocardial infarction, or a past history of myocardial infarction, stroke, or transient ischaemic attack, but also among many other categories of high risk patients (such as those having vascular procedures and those with stable angina or peripheral vascular disease). There is as yet, however, no clear evidence on the balance of risks and benefits of antiplatelet therapy in primary prevention among low risk subjects.

Collaborative overview of randomized trials of antiplatelet therapy .1. prevention of death, myocardial-infarction, and stroke by prolonged antiplatelet therapy in various categories of patients

2014 AHA/ACC Guideline for the Management of Patients With Non–ST-Elevation Acute Coronary Syndromes A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines

Circadian variation of blood-pressure

We have monitored ambulant intra-arterial blood pressure with the Oxford system in six subjects with autonomic failure who exhibited postural hypotension. Plotting pooled hourly mean values we have demonstrated a consistent circadian trend in blood pressure that was the inverse of the normal pattern, with the highest pressures at night and the lowest in the morning. In four subjects, confinement to bed did not substantially alter this pattern. Heart rate variability was much reduced in four of the subjects, but relatively normal in two in whom blood pressure variation was also less abnormal. There was a correlation of the nadir of the blood pressure measurements with the reported time of peak incidence of orthostatic symptoms. These findings are of importance in both the management and physiologic testing of patients with this condition.

Circadian variation of blood pressure in autonomic failure.

The majority of post-myocardi al infarction studies with /^-blocking drugs involved earlier generations. Newer drugs of this family with additional vasodilating and free-radical suppression properties, such as carvedilol, are now available which may improve the prognosis still further. This double-blind, randomized, placebo-controlled, parallel group study was designed to assess the extent of myocardial ischaemia in clinically stable patients 6 weeks after acute myocardial infarction and thrombolysis, and to determine the influence of carvedilol on ischaemic events during the subsequent 6 months. One hundred and one patients who remained event free at 6 weeks post myocardial infarction underwent rest and exercise thallium-201 (Tl-201) imaging. Reversible ischaemia was detected in 70 of the patients and there were 13 events in this group compared to one event in the 31 patients without ischaemia (P=007). Four of the 56 patients on carvedilol and 10 of the 45 on placebo had adverse cardiac events (/>=004). In patients with reversible ischaemia carvedilol was more effective in reducing these events than was placebo (P=003). These studies demonstrate that reversible myocardial ischaemia detected by Tl-201 imaging is present in a large proportion of clinically stable patients following thrombolysis. In these patients, there is an increased cardiac event rate which is significantly reduced by carvedilol.

The association between cardiac events and myocardial ischaemia following thrombolysis in acute myocardial infarction and the impact of carvedilol

OBJECTIVE--To compare the presentation and natural course of first myocardial infarctions in immigrant Asians and the indigenous white population in Britain and the subsequent risk states of the two groups. DESIGN--Prospective ethnic comparison of consecutive patients with first myocardial infarctions. SETTING--Secondary referrals to a coronary care unit of a district general hospital. PATIENTS--128 Men (77 white, 54 Asian) presenting consecutively with a first myocardial infarction diagnosed on the basis of clinical, biochemical, and electrocardiographic findings. END POINT--Identification of mechanisms accounting for the increased rate of ischaemic heart disease in Asians. MEASUREMENTS AND MAIN RESULTS--Infarct size was assessed by measuring the release of creatine phosphokinase (all patients), radionuclide ventriculography (50), and contrast ventriculography (103). Risk states after infarction were assessed from the degree of ventricular dysfunction as determined by exercise electrocardiography (82 patients) and from the extent of coronary atheroma as determined by coronary arteriography (103). Glucose state was measured in fasting venous blood samples. Overall the relative rate of infarction was 4.9 times higher in Asians (95% confidence interval 3.4 to 6.9) than in the white population. Moreover, the relative rate of infarction was higher in Asians in all 10 year age groups, the greatest difference being in 30-39 year olds. The mean age of the Asian denominator population was 47.1 years compared with 49.5 years in the white population. Age at infarction was less in Asians (50.2 years) than in white patients (55.5 years; mean difference 5.5 years (95% confidence interval 2.5 to 7.1]. In Asians the mean creatine phosphokinase activity was 777 (95% confidence interval 155 to 1399) U/1 higher, radionuclide ejection fraction 8.9% (1.0% to 16.9%) lower, and left ventricular fractional shortening 4.8% (1.4% to 8.2%) lower than in white patients. The extent of coronary atheroma was significantly greater in Asians. The mean numbers of plaques in vessels not associated with infarction were 3.66 (median 3.0, range 0-10) in Asians compared with 1.97 (median 2.0, range 0-6) in white patients (p less than 0.001), and a higher proportion of Asians had three vessel coronary artery disease (p less than 0.001). Asians with diabetes or impaired glucose tolerance did not differ from those with normal blood glucose values. CONCLUSIONS--Atherogenesis arises earlier in Asians, contributing to premature first myocardial infarctions. The increased incidence of diabetes in Asians may not in itself be relevant in the greater propensity to coronary atheroma in Asians.

https://www.bmj.com/content/bmj/298/6684/1345.full.pdf

First myocardial infarctions in Asian and white men.

The blood pressure response in hypertensive subjects to chronic treatment with verapamil, a calcium antagonist (or, more precisely, a slow-channel inhibitor), was studied using the Oxford system for continuous monitoring of intraarterial blood pressure. Sixteen patients underwent continuous monitoring over a 48-hour period before and after at least 6 weeks of therapy (dose range 120-160 mg three times daily). Each monitoring period included physiologic tests designed to show the effects of different types of exercise. Verapamil produces a consistent reduction of blood pressure over 24 hours, but particularly during the day. Heart rate was similarly reduced. There was no evidence of postural hypotension, and the absolute responses to dynamic and isometric exercise were reduced. The degree of reduction of the blood pressure was consistent, suggesting that slow-channel inhibitors may be appropriate for antihypertensive therapy.

Edward B. Raftery

Papers

Circadian variation of blood-pressure

Circadian variation of blood pressure in autonomic failure.

The association between cardiac events and myocardial ischaemia following thrombolysis in acute myocardial infarction and the impact of carvedilol

First myocardial infarctions in Asian and white men.

The 24-hour ambulatory blood pressure profile with verapamil.