CONSORT (Consolidated Standards of Reporting Trials) includes various initiatives formulated by the CONSORT Group to identify and rectify the effects arising from inadequate reporting of randomized controlled trials.
Deficient design and reporting of randomized controlled trials is widely acknowledged and the issues are addressed in the CONSORT statement.
CONSORT Statement:
The main document of the CONSORT Group is the CONSORT Statement which is an evidence-based, minimum list of guidelines for reporting randomized controlled trials. It elucidates a standard path for authors to prepare reports of trial results, facilitating their complete and ethical reporting, reducing the publication bias on their results, and further facilitating their critical appraisal and interpretation.
Perindopril protection against recurrent stroke study (PROGRESS) is a classic case of such inconsistencies.
The title of this study wrongly projects that perindopril, an ACE inhibitor can protect recurrent strokes. The presentation of the results of the study further leaves the statement unclear. In this study the actual meaning of the terms “active treatment” and “perindopril-based blood-pressure-lowering regimen” relates to the beneficial effects of the combination therapy (perindopril+indapamide).
The aim of PROGRESS was to test a flexible blood pressure lowering regimen but the two study arms appear to answer two different questions. One question was to evaluate the use of single ACE inhibitor perindopril against a placebo(used 2561 patients)and the seconded to test a combination of perindopril and Indapamide against double placebo (used 3544 patients). The selection of patients for adding indapamide was left to the investigator to decide but no criteria are specified in the report. The socio-economic diversity of the study population is also not specified in the report.
The two treatment arms have markedly incongruous results necessitating a separate interpretation and reporting. Further the study is deficient of a group randomized on indapamide only. Addition of the indapamide alone treatment arm would compare findings of PROGRESS with PATS (post-stroke antihypertensive treatment study) which had showed a 29% risk reduction with indapamide. [1]
Despite the finding that a blood pressure lowering has a beneficial role in post-stroke risk reduction and insufficient statistical power for any individual drug, the study conclusion is silent about it. On the contrary it is stressing the use of perindopril and indapamide as a routine treatment for post stroke patients.
In a practical scenario the results of the study need to be considered along with a number of other clinical factors related to the disease population. Possibility of side effects like orthostatic hypotension increasing the risks for falls and fractures need to be considered before prescribing antihypertensives to elderly patients. Further in elderly patients with stroke, comorbidity and life expectancy needs to be compared with the possibility of such side effects. Patients with misery perfusion in stage II ischemia are considered to have a significantly higher stroke recurrence ratio than are patients without misery perfusion. [2] Use of antihpertensives in such patients may not be appropriate.
PROGRESS was a large study in terms of cohort size and follow-up time. It supports earlier studies that showed that lowering of blood pressure helps in the secondary prevention of ischemic and haemorrhagic stroke.
It showed a relative risk reduction of 28% in patients with previous stroke and TIAs. Major vascular events were reduced by 26% in the study population. In all subgroups the combination therapy proved more significant than perindopril alone. All these findings are relevant evidence to support the lowering of blood pressure for the secondary prevention of stroke.
One of the study findings that signify a limited generalizability is the withdrawal of patients during the 4 week run in period. During this pre-randomization phase 1016 patients(14%) were withdrawn from the study due to dizziness or hypotension(3·4%), cough(2·7%), other suspected intolerance(2·3%), participant’s decision(2·0%) and an isolated case of non-fatal angio-oedema.
In general practice this would amount to 14% of the patients eligible for the perindopril and indapamide regimen and is for the treating physician to decide.
References:
[1] Wennberg R, Zimmermann C. The PROGRESS trial three years later: time for a balanced report of effectiveness. BMJ 2004;329:968 –70
[2] Kobayashi M, Okazawa H, Tsuchida T, Kawai K, Fujibayashi Y, Yonekura Y. Diagnosis of misery perfusion using noninvasive 15O-gas PET. J Nucl Med. 2006;47:1581–1586.