Involuntary weight loss without specific symptoms: a clinical prediction score for malignant neoplasm.

BACKGROUND Involuntary weight loss (IWL) is a non-specific symptom frequently found in the setting of a malignant neoplasm. There is no established diagnostic approach for patients presenting with isolated IWL, i.e. without data suggesting a particular organ involvement or system disorder. AIM To assess the clinical probability of cancer in patients with isolated IWL by means of a score based on simple clinical and laboratory parameters. DESIGN Retrospective analysis, followed by prospective model validation. METHODS We analysed data from 328 patients who were treated at our Internal Medicine Department because of isolated IWL from January 1991 to December 1997. A predictive model for cancer was developed and validated. For use in clinical practice, a prediction score was derived from the regression model. RESULTS There were 236 in-patients (72%) and 92 out-patients (28%). Malignancies were the most frequent cause of isolated IWL (35%), followed by psychiatric disorders (24%). Age, white blood count, and serum albumin, alkaline phosphatase, and lactate dehydrogenase levels were selected as the best predictors. The regression model discriminated relatively well between patients with or without a malignant neoplasm (area under the ROC curve 0.90, 95%CI 0.88-0.92). Model sensitivity was 69%, specificity 93% and positive likelihood ratio 9.9 (using a cut-off point of 0.5). DISCUSSION We believe this to be the first study to attempt a systematic approach to the diagnosis of isolated IWL. The approach, based on very simple clinical and laboratory data, should assist the physician in a rational approach to such patients.