The recent successes of genome-wide association studies and the promises of whole-genome sequencing fuel interests in the translation of this new wave of basic genetic knowledge to health care practice. Knowledge about genetic risk factors may be used to target diagnostic, preventive, and therapeutic interventions for complex disorders based on a person's genetic risk, or to complement existing risk models based on classical non-genetic factors such as the Framingham risk score for cardiovascular disease. Implementation of genetic risk prediction in health care requires a series of studies that encompass all phases of translational research, starting with a comprehensive evaluation of genetic risk prediction.
With increasing numbers of discovered genetic markers that can be used in future genetic risk prediction studies, it is crucial to enhance the quality of the reporting of these studies, as valid interpretation could be compromised by the lack of reporting of key information1, 2
. Information that is often missing includes details in the description of how the study was designed and conducted (eg, how genetic variants were selected and coded, how risk models or genetic risk scores were constructed, and how risk categories were chosen), or how the results should be interpreted. An appropriate assessment of the study's strengths and weaknesses is not possible without this information. There is ample evidence that prediction research often suffers from poor design and bias, and these may also have an impact on the results of the studies and on models of disease outcomes based on these studies.3, 4, 5
Although most prognostic studies published to date claim significant results,6, 7
very few translate to clinically useful applications. Just as for observational epidemiological studies,8
poor reporting complicates the use of the specific study for research, clinical, or public health purposes, and hampers the synthesis of evidence across studies.
Reporting guidelines have been published for various research designs,9
and these contain many items that are also relevant to genetic risk prediction studies. In particular, the guidelines for genetic association studies (STrenghtening the REporting of Genetic Association studies (STREGA)) have relevant items on the assessment of genetic variants, and the guidelines for observational studies (Strengthening the Reporting of OBservational studies in Epidemiology) have relevant items about the reporting of study design. The guidelines for diagnostic studies (STAndards for Reporting Diagnostic accuracy (STARD)) and those for tumor marker prognostic studies (Guidelines for Reporting of tumor MARKer studies (REMARK)) include relevant items about test evaluation; the REMARK guidelines also have relevant items about risk prediction.10, 11, 12, 13
However, none of these guidelines are fully suited to genetic risk prediction studies, an emerging field of investigation with specific methodological issues that need to be addressed, such as the handling of large numbers of genetic variants (from 10
s to 10
s) and flexibility in handling such large numbers in analyses. We organized a 2-day workshop with an international group of risk prediction researchers, epidemiologists, geneticists, methodologists, statisticians, and journal editors to develop recommendations for the reporting of Genetic RIsk Prediction Studies (GRIPS).