December 1998 Bulletin

Normative data collection study in third phase

Baseline norms will allow comparisons of patients

The Academy's Normative Data Collection Study moved into its third phase in November when 35,000 people across the United States were mailed questionnaires that will be used to assess pain and function in various musculoskeletal regions of their bodies.

The study's main purpose is to generate normative data representative of the general United States population that can be used to conduct data analyses to establish a set of baseline norms and benchmarks for comparison to patients or groups of patients with various musculoskeletal conditions.

"You need to have normative data for a frame of reference," said Peter C. Amadio, MD, chairman of the Outcomes Studies Committee. "You can look at the change in your patients, but can't put it in a frame of reference without knowing the scores of normal people. It isn't appropriate to think normal people have zero symptoms; most people have some aches and pains."

Along with collecting normative data, the Academy will be collaborating with John Ware, Jr., PhD, author of the SF-36 general health status questionnaire, to address an additional study and two research questions in conjunction with the Normative Data Collection Study.

In the additional study, normative data for the new SF-36 Version 2.0 will be collected through the Academy's Normative Data Collection Study. The purpose of this study is to calibrate the SF-36 version 2.0 against the existing Version 1.0 survey content and scoring algorithms. Using data from the additional study, the effect of one-week versus four-week recall periods on how respondents answer pain and function questions will be addressed. The second research question to be addressed by this study is a hypothesis that placement of the co-morbidity questions will influence the responses to the SF-36 general health status questions. Under the hypothesis, if respondents are asked about co-morbidities first they will dwell on how sick they are, which will affect their answers to the rest of the questions on the questionnaire. To test this hypothesis, the co-morbidity questions will be inserted before the general health status, pain, and function questions on some surveys and after them on others.

In order to accommodate the additional research questions, 72 different versions of the Academy questionnaires will be mailed. Each version contains a common set of co-morbidity questions along with a set of questions specific to pain and function of a specific body location-upper extremity, lower extremity, etc., and one of two versions of the SF-36.

The Normative Data Collection Study is the fourth step in a process designed to carry out the Academy's outcomes vision. It follows development of a series of musculoskeletal functional assessment questionnaires, a pilot study to test the technical feasibility of collecting high quality data from a variety of practices using a variety of software packages, and the implementation in 1996 of the MODEMS (Musculoskeletal Outcomes Data Evaluation and Management System) Program to collect outcomes information from physicians' offices across the county and to establish a national outcomes database.

Dr. Amadio said the normative study data will be incorporated into the MODEMS database so that MODEMS participants will be able to compare their patients with patients of other doctors and with normal people.

The study is being conducted for the Academy by the National Research Corporation, of Lincoln, Neb. It is expected to be completed in late spring or early summer of 1999. The Academy's current plans are to publish the results of Normative Data Collection Study in book chapter and journal article formats.

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