Patients' perceptions versus medical testing of function in women with lymphangioleiomyomatosis (LAM)

Lymphangioleiomyomatosis (LAM), a rare pulmonary disease that occurs primarily in women is characterized by progressive cystic lung lesions causing respiratory failure, which may require lung transplantation. It has been observed that in diseases of the lungs, objective medical tests frequently do not translate to subjective functional status. However, patient's perceptions of functional status directly impact quality of life. In order to evaluate this relationship in LAM, a cross sectional study of 31 lung transplant candidates and 43 lung transplant recipients with LAM was conducted to evaluate functional status. Objective tests (Pulmonary function tests, PFTs, 6 min walk) were obtained in 19 candidates and 23 recipients, and subjective function was assessed in all women using the Functional Performance Inventory. For both groups statistically significant relationships emerged between forced vital capacity with subjective measures of function including total, social and recreational function (P < 0.05). As well diffusing capacity related significantly to total function, ability to maintain household chores, body care, and social function (P < 0.05), where higher scores were associated with better subjective function. Forced expiratory volume in one second was not found to significantly relate to subjective function in these groups, except the physical exercise domain in transplant recipients. However, despite better PFT results in double lung transplant recipients, no differences were found in subjective measures of function between single and double lung recipients. Results suggest that clinicians need to better recognize that certain aspects of spirometry/6 min walk tests do not necessarily correlate well with patient's perceptions of their function. This has implications for the assessment and follow-up of women living with LAM; considering subjective aspects of function may help focus interventions and improve quality of life.