Development and validation of the Nightingale Symptom Assessment Scale (N-SAS) and predictors of the quality of life of the cancer patients in Turkey

Abstract

Purpose Treatment-related side effects have an adverse impact on the health-related quality of life (HRQoL) of cancer patients undergoing chemotherapy. This study is a description of the validity and responsiveness demonstrated by a new cancer and cancer treatment-specific symptom scale – the Nightingale Symptom Assessment Scale (N-SAS) - which was developed and validated to address the QoL of Turkish cancer patients. Method The comprehensiveness and clarity of the scale was assessed using 10 patients and pilot testing was carried out with 179 patients. A sample of 374 cancer patients who had received chemotherapy participated in the main study. Descriptive statistics were calculated and comparative tests and factor analysis were performed. Results The internal reliability of N-SAS was examined and the validity of this scale was determined by correlation with FACT-G. The scale showed high internal reliability, Cronbach's α for the subscales varied between 0.81 and 0.87 and was 0.93 for the tool. Longitudinal analyses showed that changes in N-SAS scores were strongly correlated with changes in FACT-G. Multivariate analysis revealed that having a metastatic cancer diagnosis, having a low level of income, receiving taxane-based therapy and being a woman were the most important predictive factors for the well-being of the cancer patients in this study. Conclusions The high correlation with the FACT-G suggests that the new scale is a valid instrument that can be used to evaluate the effect of antineoplastic therapies on a cancer patient's QoL and can help guide nursing care as well as track the improvement of patients' HRQoL.