PHILADELPHIA--The incidence and prevalence of late diagnosis of cystic fibrosis (CF) are increasing, and patients given a CF diagnosis as adults differ from those who received the diagnosis as children.[1] In 1996, the incidence of late-diagnosed CF was 7.8%, up from 5.8% in 1994.

To determine the association between age at diagnosis and selected demographic and health status variables, Widerman et al analyzed the 1996 data from the Cystic Fibrosis Foundation's annual registry to determine how the 813 patients with late-diagnosed CF differed from the 6,622 adults who had been given a CF diagnosis before age 18 years. They also examined how those differences were associated with gender.

The researchers reported that adults receiving a CF diagnosis after age 18 years were significantly more likely to have better lung function and to live longer than those diagnosed before age 18. Patients with late diagnoses were also significantly less likely to carry the deltaF508 CF gene mutation (the mutation most commonly associated with CF) and to be colonized with Pseudomonas aeruginosa or Burkholderia cepacia. Patients with late diagnoses were also significantly less likely to require enzyme replacement therapy.

Widerman et al found that patients with late diagnoses were, as a group, older at the time of the study than were those who received the diagnosis before age 18 (37 vs 26 years). Perhaps because they were older, late-diagnosed CF patients were more likely to be college graduates (41% vs 28%), employed full-time (48% vs 35%), and married (73% vs 35%). "These significant differences … may reflect plans made without knowledge of CF, milder disease expression, or the average age difference of 10 years between groups," the authors reported.

Over half the adults with CF were men, but women were significantly more likely to receive a late diagnosis and more likely to have milder disease. While respiratory symptoms most frequently led to the diagnosis of CF for all adults, there was more diversity in conditions leading to diagnosis for men.

"Why women are more likely to be diagnosed late is an interesting and puzzling finding," lead author Eileen Widerman, PhD, said in an interview with PULMONARY REVIEWS. "As we suggest in the article, women's complaints may not be taken seriously by physicians, so that women are diagnosed later. For instance, in an earlier study, two women told me their physicians diagnosed them as anorexic and wouldn't believe they were eating. Others told me they were accused of seeking attention via their symptoms."

Childbearing might also be a factor, according to Dr. Widerman, an Assistant Professor at Temple University in Philadelphia. "I am aware of a number of cases in which women were diagnosed either after giving birth to a child with CF or when a pregnancy resulted in increased and worsening symptoms," she said.

In their study, Dr. Widerman and her coauthors reminded physicians to be aware that "a diagnosis of CF is possible in an adult; that patients who are part of racial and ethnic minorities can have CF; and that adults with CF can present with a range of symptoms, conditions, and/or complications, some of which are gender-related."

The researchers also stressed that late-diagnosed CF patients have unique needs in terms of education, treatment, and support. "Psychosocially, those who receive diagnoses as adults must come to terms with having a life-threatening disease and must reconcile CF treatment and care with the demands of established lifestyles," they wrote.

Educationally, such patients are likely to require assistance applying CF information to adult medical and life situations because this material has primarily been developed for those receiving diagnoses in childhood. Medically, late-diagnosed CF patients need treatment that recognizes gender-related and other differences in CF expression and progression.

--Janis Kelly

Reference
1. Widerman E, Millner L, Sexauer W, Fiel S. Health status and sociodemographic characteristics of adults receiving a cystic fibrosis diagnosis after age 18 years. Chest. 2000;118:427-433.

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