Alba Mitchell

A New Measure of Health Status for Clinical Trials in Inflammatory Bowel Disease

We have developed a measure of subjective health status (quality of life) for patients with inflammatory bowel disease (IBD). Ninety-seven patients with IBD described problems they had experienced as a result of the disease; the 32 most frequent and important items were included in the Inflammatory Bowel Disease Questionnaire (IBDQ). Sixty-one IBD patients were evaluated twice. One month separated the evaluations, at which disease activity indices, the IBDQ, and a number of other questionnaires were administered. Reproducibility studies in 19 stable patients showed improvement in scores, but also a small within-person standard deviation. Responsiveness studies revealed large changes in scores in patients who had improved or deteriorated and suggested that the IBDQ was more responsive than a general health status measure. Responsiveness appeared greater in patients with ulcerative colitis than in those with Crohns disease. Predicted and observed correlations between changes in IBDQ score and changes in other measures were similar. We conclude that although further testing is required, particularly in examining the relation between changes in the IBDQ and changes in the activity of Crohns disease, the IBDQ shows promise as a measure of health status for clinical trials in IBD.

RESPONSIVENESS AND VALIDITY IN HEALTH STATUS MEASUREMENT: A CLARIFICATION*

We present data from two studies which clarify the relationship between the responsiveness and validity of instruments designed to measure health status in clinical trials. In a controlled trial of long vs short duration adjuvant chemotherapy for women with Stage II breast cancer, the Breast Cancer Chemotherapy Questionnaire (BCQ) proved valid as a measure of subjective health status and was able to distinguish long vs short arms. Well validated measures of physical and emotional function developed by the Rand Corporation were unable to distinguish between the two groups. The Eastern Co-operative Oncology Group Criteria (ECOG) distinguished the two groups, but failed criteria of clinical sensibility as a measure of subjective health status. In a study of patients with Crohns disease and ulcerative colitis, the Inflammatory Bowel Disease Questionnaire (IBDQ) showed small intrasubject variability over time. Gobal ratings of change showed moderate to high correlations with changes in IBDQ score, and patients who reported overall improvement or deterioration showed large changes in IBDQ score. Each of these findings support, in different ways, the reproducibility, validity, and responsiveness of the questionnaire. While the same data can at times bear on both validity and responsiveness, when assessing evaluative instruments it is useful to make a conceptual distinction between the two.

Definition of an advanced nursing practice role in the NICU: the clinical nurse specialist/neonatal practitioner.

WE SURVEYED 655 health professionals affiliated with tertiary level neonatal intensive care units in Canada and the United States to define an expanded role for nurses in neonatology and to determine the educational requirements for the role. The role, comprising advanced clinical practice, educational, research, and administrative responsibilities, is a blend of nurse practitioner and clinical nurse specialist activities. Based on survey findings, a neonatal stream within the existing Master of Health Sciences program at McMaster University was developed. To date, 15 clinical nurse specialists/neonatal practitioners (CNS/NPs) are employed in five neonatal intensive care units in Ontario and other related institutions. A randomized trial to evaluate these individuals is in progress.

The Likelihood of Remaining Normotensive Following Antihypertensive Drug Withdrawal

Objective:To determine the proportion and characteristics of mild hypertensives who remain normotensive after withdrawal from drug treatment.Design:Longitudinal descriptive study.Setting:A university family practice unit (FPU) and a large steel company (DOFASCO) in Hamilton, Ontario.Patients:Participants were 107 of 125 (86%) eligible hypertensives at the two sites; 103 (96%) subjects completed the study.Intervention:Subjects discontinued antihypertensive medication and were followed until blood pressure (BP) became elevated or for 12 months, whichever was shorter.Measurements and main results:BPs were monitored according to a predefined schedule and before, during, and after mental and physical stress tests. Thirty-eight (37%, 95% confidence interval [CI] 27–46%) subjects remained normotensive at 12 months. Predictors of remaining normotensive included lower medicated standing diastolic blood pressure (DBP) (87.6 versus 91.8 mm Hg, 95% CI for the difference 2.2–6.2, p<0.001) and longer duration of normotension on drugs (12.6 months versus 8.7, 95% CI for the difference 0.9–6.9, p=0.012). There was no significant relationship between maintenance of normotension and age, medication potency, duration of hypertension, weight, lying BP, change in heart rate, or BP during mental or physical stress tests; the power to detect a clinically important difference in lying DBP was 99% but for other variables was lower (21 – 75%).Conclusions:The probability of hypertensives’ remaining normotensive for one year after drug withdrawal increases as the medicated standing DBP decreases and as the number of months of BP control while on medication increases. Studies with larger sample sizes are warranted to determine whether other variables may be significant predictors.

Use of certainty of opinion data to enhance clinical decision making

Clinical decision making and diagnostic testing procedures are frequently evaluated using indices such as sensitivity and specificity. These indices require an assumption that the underlying disease state or the diagnostic test result is binary, which may be an unreasonable assumption in many clinical situations. They also fail to recognise the potential for different degrees of diagnostic confidence. In this paper, we report some data from a clinical study of postpartum mothers in which, in addition to the diagnostic result, an expression of certainty or strength of belief was ascertained. We illustrate how the certainty of opinion data can be combined with the diagnostic opinion in order to enhance the interpretation of the study, and the implications for improving the accuracy of clinical decision making in general.