Malnutrition and gastrointestinal dysfunction as prognostic factors for survival in familial amyloidotic polyneuropathy

Abstract

Objectives. To describe the evolution of nutritional and neurological complications in a Swedish population of patients with familial amyloidotic polyneuropathy, and to identify prognostic factors and useful tests for monitoring the progress of the disease. Design. Prospective and retrospective study of patients with familial amyloidotic polyneuropathy. Setting. Tertiary referral centre. Subjects. Twenty-seven patients with familial amyloidotic polyneuropathy, and a symptomatic onset before the age of 50. Main outcome measures. Age at onset, duration of disease before death, serum albumin, body mass index (BMI), duration and grade of peripheral neuropathy and gastrointestinal disturbances. Faecal fat, xylose test and ⁷⁵selenohomocholic acid-taurine (SeHCAT) test were used for assessment of malabsorption. Results. Thirteen patients died during the study period after a disease duration of between 9 and 18 years (mean 13). A short time interval between the onset of neurological and of gastrointestinal symptoms had greater impact on survival than age at onset in this selected group of patients (r = 0.65; P = 0.017). Malnutrition was evaluated by multiplying the [body weight (kg)/height² (m)] with the serum albumin to compensate for oedema. This modified body mass index (mBMI) was significantly correlated to the number of years before death (r = 0.89; P < 0.0005) and to the duration of gastrointestinal symptoms (r = —0.66; P < 0.0005), but not to duration of disease (r = —0.2; P = 0.20). Polyneuropathy was graded according to functional capacity from I to IV (PND score) and was correlated to the number of years before death and mBMI, but not to serum albumin. The SeHCAT test for bile acid malabsorption was significantly correlated to the duration of gastrointestinal symptoms and to mBMI (r = —0.67; P = 0.0003 and r = —0.62; P = 0.003, respectively). Conclusion. The investigation disclosed that a short time interval between the onset of neurological and of gastrointestinal symptoms is associated with a decreased survival time. The mBMI was closely related to time before death, duration of gastrointestinal disturbances, malabsorption and functional capacity. The mBMI appears to be well suited to monitoring disease progress and gives prognostic information.