Serious Infections in Children with Lupus: Uncommon But Importantby Dr Bud Wiederman MD, MA, Evidence eMended Editor, Grand Rounds

This administrative database study has some important caveatsfor primary care providers, in spite of the limitations in study design.Source: Hiraki LT, Feldman CH, Marty FM, et al. Serious infection rates among children with systemic lupuserythematosus enrolled in Medicaid [published online ahead of print February 19, 2017]. Arthritis Care Res.doi:10.1002/acr.23219. See AAP Grand Rounds commentary by Dr. Gloria Higgins (subscription required).

First, let's get the limitations out of the way. I like to call administrative database studies the "grain of salt" studydesign.* Administrative databases have information based on billing codes and the like, with little to no clinicaldetail available. Researchers can find out diagnoses, medications administered, duration of hospitalizations, andsimilar details, but such databases generally do not contain lab results nor any nuances of care that would beavailable from a true chart review. This study of US children with systemic lupus erythematosus (SLE) is takenfrom a Medicaid administrative database and has some good pearls for frontline pediatric providers.

The researchers looked at the years 2000 - 2006 for Medicaid-enrolled children 4 - 17 years of age, and foundonly 3500 children with that diagnosis. If you spread that over the entire country (actually in this study, 47 statesplus DC were included), the average pediatric primary care practice would likely have only a few SLE patients.Infection rates were in the ballpark of 10 per 100 person-years, so a pediatrician in a medium-sized practice hasa reasonable chance of never seeing a child with SLE and serious infection. Still, those same providers need tobe able to recognize such situations.

What were the infections? Here, we again need to deal with the grain of salt problem. The investigatorsexcluded systemic candidiasis diagnoses, because of prior data suggesting that discharge diagnosis codeswere not accurate for that entity. Furthermore, they didn't count central nervous infections, because of thedifficulty of distinguishing infectious causes from lupus encephalitis. Not only does that mean the 10 per 100person-years number may be too low, it also cuts out a chunk of very important diagnoses from consideration.With that caveat, bacterial infections (mainly pneumonia, bacteremia, and cellulitis) accounted for the vastmajority of infections, with herpes zoster the most common viral diagnosis. Fortunately, all of those diagnosesshould be familiar to pediatric primary care providers. It didn't appear that the authors attempted to determinehow many of the bacteremic episodes were associated with indwelling venous catheters; I suspect that would betough to do with this database.

So, I'd take this information to mean that front line providers, when evaluating a child with SLE and infectionconcern, should be careful to perform a thorough evaluation of breath sounds and skin in particular, plus have alow threshold for obtaining blood culture as part of the initial evaluation. It would be interesting to see a chartreview study to determine the yield of blood culture in this setting.

Copyright © 2017 American Academy of Pediatrics

*In a little over 6 months, I've gone from a spoonful of sugar to a grain of salt. Of course, I had to do my ownevidence search to find the origin of the term "grain of salt," and it seems it is open to debate. Clearly, Pliny theElder deserves some credit since he published it, as part of a recipe for a poison antidote. Regardless of itsorigins, my point is the same: studies utilizing administrative databases have serious limitations. Don't rely onthe precision of the findings, that's for future studies to define. However, clinicians can still find some savorybites among the grains.

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Copyright © 2017 American Academy of Pediatrics