Isolated involuntary weight loss: Epidemiology and predictive factors of malignancy.

Background And Objectives: The aims of the study were to analyse the epidemiology, prognostic and predictive factors of malignant disease on isolated involuntary weight loss (IIWL) and to know the effectiveness of the quick diagnosis unit in the evaluation of the process.

Material And Methods: Prospective observational study realised from 2006 to 2015 of all patients who were evaluated with IIWL in the quick diagnosis unit. Demographic, clinical, diagnostic and evolutive variables were analysed. Through the analysis of logistic regression, predictive factors of malignant disease and prognostic factors were identified.

Results: Of the 533 registered patients, 55.1% were≥65 years old. The diagnostics were: non-neoplastic organic disorders in 214 patients (40.2%), psychiatric disorders in 144 (27%), cancer in 81 (15.2%) and unknown cause in 94 (17.6%). In 66.7% of the patients with cancer, there was an increase of serum tumour markers (STM). Being over 60 (OR: 2.57; 95% CI: 1.27-5.77; P=.01) %), male (OR: 3.23; 95% CI: 1.52-6.87; P=0.002), increase of an STM (OR: 2.38; 95% CI: 1.17-4.8; P=0.016) and more than one STM (OR: 6.51; 95% CI: 2.62-16.13; P=0.000) were identified as predictive factors of malignancy. Mortality was 14.2%; the diagnosis of cancer (OR: 47.61; 95% CI: 20.76-109.19; P=0.000) was identified as a prognostic factor.

Conclusions: IIWL is a clinical syndrome that requires a study with a sequential protocol and follow-up. STM were identified as predictive factors of malignancy.