Despite a higher overall frequency of pneumonia and greater use of immunosuppressive therapies, the occurrence of serious pneumonias has decreased in Finnish children with juvenile idiopathic arthritis (JIA) over time, a study shows.
The researchers hypothesized that this may reflect better clinical care and early detection of lung infections in these children.
The work also suggested that active JIA, the presence of comorbidities, or simultaneous diseases, and receiving combination therapy may be associated with an increased risk of developing pneumonia. However, there was no link between the use of immunosuppressants and pneumonia severity.
The study, “Decreasing trend in the incidence of serious pneumonias in Finnish children with juvenile idiopathic arthritis,” was published in the journal Clinical Rheumatology.
The main treatment goals in JIA today include achieving inactive disease as early as possible in children’s lives and preventing joint damage caused by inflammation. The development of disease-modifying anti-rheumatic drugs (DMARDs) — which are designed to block inflammation — has significantly improved the lives of children with JIA.
Yet, the immune system suppression that occurs with standard JIA medications, such as DMARDs and glucocorticoids — along with the disease itself and the presence of comorbidities — have been associated with an increased risk of infections in these children.
A recent analysis of the 15-year period between 1999 and 2014 showed that pneumonia — one of the most common serious infections in JIA patients — has become more frequent in Finnish children with the disease. That increase has been mirrored by a significant jump in the use of DMARDs in this patient population during the same time period.
Now, that same team of researchers set out to determine the severity of pneumonia in these children, and whether it was associated with the use of immunosuppressive therapy.
The team analyzed data from 59,048 JIA patient-years — a measure obtained by multiplying the number of persons per time — between 1998 and 2014, using a national patient registry that covers the entire hospital network in Finland. The number of children with JIA per year in the registry varied between 2,292 and 3,575 from 1998 through 2006, and between 3,633 and 4,511 in the years 2007 to 2014.
Pneumonia was classified as serious if the child was hospitalized or given antibiotics directly into the bloodstream. It was deemed hospital-acquired if the illness developed 48 hours or later following hospital admission for reasons other than lung infection.
The results showed 157 pneumonia episodes — of which 111 (70.7%) were serious — in 140 children with JIA. Only one case was hospital-acquired.
The mean age of children with at least one pneumonia episode was 9.4 years; 83 (59.3%) of the children were girls. Most had either oligoarthritis (45%) or polyarthritis (45.7%).
The rate of serious pneumonia decreased from the first time period — 1998 through 2006 — to the second, from 2007–2014. The team hypothesized that this trend may be a result of better contact between patients and the health care system, which would promote earlier detection and treatment of lung infections.
“It is also worth noting that a decrease in pneumonia rates has been reported after introduction of pneumococcal vaccination into the Finnish national vaccination program in 2010,” the researchers said.
Data also showed that nearly half of the children with pneumonia had active disease, comorbidities — with asthma (17.9%) and Down syndrome (7.1%) being the most common — and were receiving combination therapy.
At the time of the pneumonia episodes, 86% of the children were receiving DMARDs, with 61.8% receiving methotrexate and 25.8% taking TNF inhibitors. This inhibitors block the activity of TNF-alpha, a pro-inflammatory molecule.
Among the children treated, 15 (10.7%) had recurrent pneumonias; 12 of them had comorbidities. Patients were taking DMARDs during 28 of the 32 (87.5%) recurrent pneumonia episodes.
The team noted that they found no significant association between pneumonia severity and the use of DMARDs or glucocorticoids.
The data showed that, overall, “active JIA, comorbidities and combination medication were associated with nearly half of the pneumonias,” the researchers said.
Still, future studies are required to confirm these findings and to evaluate the potential association between pneumonia and specific types of JIA, they added.
“Clinicians should always keep in mind the possibility of serious infectious complications in these immunocompromised patients,” the investigators said.