Researchers, consumers, health care pro­viders and policy makers are inundated with large amount of information from scientific journals. It is vital to integrate this vast infor­mation into valid evidence and use it for rational decision making. Systematic reviews establish where the effects of health care are consistent and research results can be applied across populations and settings. They also outline the differences in treatments and sig­nificant variations in treatment effects(1). Cochrane library is an electronic database of such systematic reviews which emphasize limitation of systematic and random errors, thus providing more reliable results upon which to draw conclusions and make deci­sions(2,3). It builds on the work of a large number of voluntary contributors with declared conflicts of interest coordinated by the Collaborative review groups who have taken up the daunting task of reviewing the effects of health care(4). It thus encourages bias free evidence based practice of medicine.

The need for clinical practice guidelines in management of children with asthma in India has always been felt. However, all clinical practice guidelines need to be based on scientific evidence. The statements or recommendations need to be transparent about the evidence or its absence. In this way decisions can be made about local applicability and implementation can be made with greater confidence. Recommendations can be graded into three categories on the basis of quality of evidence used to support them(5). In the hierarchy of evidence, Grade A requires a systematic review of randomized controlled trials or at least one randomized controlled trial to support the conclusions. Grade B requires avail­ability of well controlled clinical studies and Level C is based on opinions or clinical experience of the respected authorities. This happens in the absence of good quality studies.

A Consensus Conference was held in April 1998 at the Advanced Pediatric Center to formulate evidence based guidelines for the management of asthma in children in India. A total of 15 experts from different parts of the country participated in the proceedings. In order to make the guidelines evidence based, Cochrane Library along with other literature data bases was searched before and during the conference and the updated information used during the preparation of the document. The results of this exercise are being reported to sensitize the readers about the methodology used in policy research in order to make the guidelines evidence based.

Methods

Using the "advanced search" mode in The Cochrane Library (1998 Issue 2) on "asthma" a total of 4213 hits were obtained. The Cochrane data base of systematic reviews (CDSR) gave 57 items out of 737 in total. There were 20 completed reviews out of 377 total and 37 protocols out of a total of 360. Data base of reviews of effectiveness gave 17 hits relating to asthma out of a total of 1631. There were 7 quality assessed systematic reviews. ACP (American College of Physicians) journal club had two abstracts of reviews. There were six other assessed reviews and two unasessed reviews. Cochrane controlled trial register (CCTR) gave 4129 hits out of a total of 179546 trials that related to asthma. There were nineteen controlled trials listed under the year 1998. Nine completed reviews and 14 protocols (Table /) were helpful in formulating the guidelines and in further location of the relevant evidence. Reviews were also helpful in settling issues where the expert opinion was controversial. Sixty-two per cent more trials could be accessed by using Cochrane library rather than accessing Medline in Internet during the same period.

Comments

Traditional reviews are now being replaced by systematic reviews. Wider recognition of the key role of reviews in synthesizing and disseminating the results of researches prompted people to consider the validity of reviews. In the 1970 and early 1980s psychologists and social scientists drew attention to the systematic steps needed to minimize bias and random errors in reviews of research. Cochrane library has a data base of systematic reviews which have been produced by the concerted efforts of several Cochrane entities. It is a valuable document to aid the process of decision making and in formulating evidence based guidelines. It also provides a source for ready reference for making clinical decision compared to Medline which simply lists the trials. Although increasing numbers of systematic reviews in the field of asthma are being done by the Cochrane Airways Group which have been published in the Cochrane Library, a lot needs to be done in our country for the creation of scientific evidence in this field. There are very few randomized controlled trials which can provide Grade A evidence. Several research questions especially relating to prevention of asthma have not yet been taken up. Hence there is lot of scope for updating the guidelines as the body of information expands.

TABLE I

Results of Cochrmle Data Base Search

                                       Meenu Singh,
                                         Lata Kumar,
              Advanced Pediatric Center,
                 Post Graduate Institute of
Medical Education and Research,
                          Chandigarh 160012,
                                                     India.