Bias with respect to socioeconomic status: A closer look at zip code matching in a pneumococcal vaccine effectiveness study.

In 2010, 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in the US for prevention of invasive pneumococcal disease in children. Individual-level socioeconomic status (SES) is a potential confounder of the estimated effectiveness of PCV13 and is often controlled for in observational studies using zip code as a proxy. We assessed the utility of zip code matching for control of SES in a post-licensure evaluation of the effectiveness of PCV13 (calculated as [1-matched odds ratio]*100). We used a directed acyclic graph to identify subsets of confounders and collected SES variables from birth certificates, geo-coding, a parent interview, and follow-up with medical providers. Cases tended to be more affluent than eligible controls (for example, 48.3% of cases had private insurance vs. 44.6% of eligible controls), but less affluent than enrolled controls (52.9% of whom had private insurance). Control of confounding subsets, however, did not result in a meaningful change in estimated vaccine effectiveness (original estimate: 85.1%, 95% CI 74.8-91.9%; adjusted estimate: 82.5%, 95% CI 65.6-91.1%). In the context of a post-licensure vaccine effectiveness study, zip code appears to be an adequate, though not perfect, proxy for individual SES.

Ototoxicity in children with high-risk neuroblastoma: prevalence, risk factors, and concordance of grading scales--a report from the Children's Oncology Group.

PURPOSE: Platinum-based therapy is the mainstay for management of high-risk neuroblastoma. Prevalence of platinum-related ototoxicity has ranged from 13% to 95% in previous reports; variability is attributable to small samples and disparate grading scales. There is no consensus regarding optimal ototoxicity grading. Furthermore, prevalence and predictors of hearing loss in a large uniformly treated high-risk neuroblastoma population are unknown. We address these gaps in our study. PATIENTS AND METHODS: Audiologic testing was completed after administration of cisplatin alone (< 400 mg/m(2); exposure one) or after cisplatin (400 mg/m(2)) plus carboplatin (1,700 mg/m(2); exposure two). Hearing loss was graded using four scales (American Speech-Language-Hearing Association; Brock; Chang; and Common Terminology Criteria for Adverse Events, version 3 [CTCAEv3]). RESULTS: Of 489 eligible patients, 333 had evaluable audiologic data. Median age at diagnosis was 3.3 years. Prevalence of severe hearing loss differed by scale. For those in the exposure-one group, prevalence ranged from 8% per Brock to 47% per CTCAEv3 (Brock v CTCAEv3 and Chang, P < .01; CTCAEv3 v Chang, P = .16); for those in the exposure-two group, prevalence ranged from 30% per Brock to 71% per CTCAEv3 (all pair-wise comparisons, P < .01). In patients requiring hearing aids, hearing loss was graded as severe in 49% (Brock), 91% (Chang), and 100% (CTCAEv3). Risk factors for severe hearing loss included exposure to cisplatin and carboplatin compared with cisplatin alone and hospitalization for infection. CONCLUSION: Severe hearing loss is prevalent among children with high-risk neuroblastoma. Exposure to cisplatin combined with myeloablative carboplatin significantly increases risk. The Brock scale underestimates severe hearing loss and should be used with caution in this setting.

Yield of screening for long-term complications using the children's oncology group long-term follow-up guidelines.

PURPOSE: The Children's Oncology Group Long-Term Follow-Up (COG-LTFU) Guidelines use consensus-based recommendations for exposure-driven, risk-based screening for early detection of long-term complications in childhood cancer survivors. However, the yield from these recommendations is not known. METHODS: Survivors underwent COG-LTFU Guideline-directed screening. Yield was classified as negligible/negative (< 1%), intermediate (≥ 1% to < 10%), or high (≥ 10%). For long-term complications with high yield, logistic regression was used to identify subgroups more likely to screen positive. RESULTS: Over the course of 1,188 clinic visits, 370 childhood cancer survivors (53% male; 47% Hispanic; 69% leukemia/lymphoma survivors; median age at diagnosis, 11.1 years [range, 0.3 to 21.9 years]; time from diagnosis, 10.5 years [range, 5 to 55.8 years]) underwent 4,992 screening tests. High-yield tests included thyroid function (hypothyroidism, 10.1%), audiometry (hearing loss, 22.6%), dual-energy x-ray absorptiometry scans (low bone mineral density [BMD], 23.2%), serum ferritin (iron overload, 24.0%), and pulmonary function testing/chest x-ray (pulmonary dysfunction, 84.1%). Regression analysis failed to identify subgroups more likely to result in high screening yield, with the exception of low BMD (2.5-fold increased risk for males [P = .04]; 3.3-fold increased risk for nonobese survivors [P = .01]). Screening tests with negligible/negative (< 1%) yield included complete blood counts (therapy-related leukemia), dipstick urinalysis for proteinuria and serum blood urea nitrogen/creatinine (glomerular defects), microscopic urinalysis for hematuria (hemorrhagic cystitis, bladder cancer), ECG (anthracycline-related conduction disorder), and hepatitis B and HIV serology. CONCLUSION: Screening tests with a high yield are appropriate for risk groups targeted for screening by the COG-LTFU Guidelines. Elimination of screening tests with negligible/negative yield should be given consideration.