Background: Our goal was to establish the clinical and genetic characteristics of patients diagnosed with adult-onset cystic fibrosis (CF).
Patients and method: This was a retrospective observational descriptive comparative study of CF patients according to their age at the time of diagnosis. All adult patients (> 16 years old) attended in our CF Unit until November 2001 were included in the study. Those patients diagnosed of CF at their childhood (< 16 years old) were categorized as Group A patients, and those diagnosed in adulthood (>= 16 years old) were categorized as group B patients. Anthropometric parameters, respiratory and digestive clinical abnormalities, chest and abdominal radiological exams, sputum bacteriology, respiratory function and genetic tests were evaluated. Statistical analysis between groups was performed by comparing chi square test for qualitative values and the Student t test for quantitative values.
Results: One hundred and eleven patients (60 women, mean age 28, range 16-69 years) out of a total sample of 245 (45.3%) patients attended at the CF unit were enrolled in the study. Group A included 61 patients (32 women; mean age 23) and group B included 50 patients (28 women; mean age 32). The comparative study between both groups showed that patients in group B were older, had a higher weight and less incidence of initial digestive abnormalities, pancreatic insufficiency, malnutrition, hepatic disease, chronic bronchial colonization by Pseudomonas aeruginosa, admissions, lung transplantation and deaths due to CF. On the contrary, these patients had a higher incidence of pancreatitis, allergic bronchopulmonary aspergillosis at diagnosis and better respiratory function test parameters. The sweat test was negative in 4 patients of group B and 1 of group A. The genetic study showed 31 different CF mutations, from which only 10 were observed in group B.
Conclusions: CF can also be diagnosed in adult age. Patients diagnosed in adulthood have less digestive abnormalities, better lung function and different genetic mutations. The sweat test can be negative or undetermined. These patients also display a better prognosis.