Abusive Head Trauma During a Time of Increased Unemployment: A Multicenter Analysis

DISCUSSION

These data show a significant increase in the rate of AHT in a 74-county region during a recession compared with the 4-year period before it. Although it is not possible to prove a causal relationship between the AHT rate and the economy with our analysis, we believe the data are compelling enough to influence policy and clinical decisions. Specifically, the presence of an association between the economy and the AHT rate should be sufficient to spur a discussion of specific stressors and mediators of these stressors and how they could be modified to decrease the risk of AHT to young children. From a clinical perspective, this association might warrant changes in the threshold for physicians to evaluate for AHT during times of economic stress in the same way that physicians change the threshold to test for and treat pertussis during a pertussis outbreak.

The relationship between the recession and the AHT rate might not be surprising given previous data that supported an association between poverty and all types of physical abuse. However, to our knowledge, this is the first study to focus on a specific exposure, the recession, and a specific outcome measure, county-level AHT rates. We did not assess individual poverty per se but evaluated the recession as a societal-level risk factor that can have an effect on the entire population—those above or below the poverty line. The ability of the time-series design to reveal societal-level risk is an important advantage of this approach. Although work in public health is often limited to identifying individual-level risk factors to identify people at high risk, the greatest improvements in a population's health are likely to derive from societal interventions, because the majority of cases of poor public health outcomes arise outside the more easily identified extremes of risk. Therefore, although targeting people at high risk can have a dramatic effect on individual risk, because only a small percentage of people are at high risk, this approach might not have a major effect on population-level rates.

The Pennsylvania data for children aged 0 to 1 year (Table 2) allow for comparison to published studies. In the study by Keenan et al,² the incidence of AHT in children aged 0 to 1 year was 29.7 in 100 000 (95% CI: 22.9–36.7). Although this incidence of AHT is lower than the Pennsylvania prerecession incidence, it is likely explained by differences in definitions; only children who were admitted to an ICU or died were included in the Keenan et al study. Using these criteria, 37% of our subjects would have been excluded. Our prerecession rate of 46.0 in 100 000 is similar to the preintervention rate of 41.5 in 100 000 reported by Dias et al²⁴ before implementation of an AHT primary prevention program. The AHT rate in the Washington region is lower than the rate in the Keenan et al study; this result is likely related to the relatively small number of children, which is reflected in the wide CIs.

Our results are in contrast to both the 2008 and 2009 official reports on child maltreatment,^18,19 which documented decreases in the rate of all types of abuse including physical abuse during the recession. This result has led some to suggest that the recession did not affect child maltreatment.²⁵ The difference in the findings might be a result of the differences in data sources and definitions and highlights why it is imperative to use multiple data sources when evaluating rates of child maltreatment. The official reports on child maltreatment are based on cases of substantiated abuse by Child Protective Services. Substantiation rates vary greatly between states and depend on multiple factors. The AHT data in our study are based on medical diagnoses. It is also possible that the overall rate of child physical abuse decreased during the recession but that the rate of AHT increased. The annual report on child maltreatment does not address AHT specifically.

The lack of an increase in the number of noninflicted TBI cases is in contrast to results from the study by Keenan et al,⁸ in which both the rate of AHT and the rate of non-inflicted TBI increased after a natural disaster. This difference might reflect differences in the risk to children after natural disasters compared with the risk during an economic recession. The increase in the rate of noninflicted TBI after a natural disaster might be related to environment hazards and less parental supervision. There might, in fact, be an increase in the amount of time that parents spend with their young children during a recession because of job loss; this additional time might be a risk factor for AHT.²⁶ Job loss might also force a caretaker who has previously not provided child care to assume a caretaking role. Because of the different stressors in a recession compared with those in a natural disaster, strategies for decreasing the effect of these stressors on children need to be different.

We do not believe that the increased rate of AHT during the recession is related to increased recognition. One of the strengths of our study is the stringency with which both subjects and sites were selected. Hospitals included in the study had a stable CPT throughout the study period. As a result, there were unlikely to be significant shifts in the evaluation of cases. In addition, we included only patients with unequivocal AHT. These children generally are not the ones whose injuries go unrecognized. Including only unequivocal AHT cases decreased the number of eligible subjects, might have affected the magnitude of the increase observed, and makes it likely that our incidence is an underestimate of true incidence.

We also do not believe that the increase is the result of changes in AHT primary prevention programs. Pennsylvania requires education of all new parents about AHT²⁷; compliance with this legislation remained high throughout the study period.²⁸ Ohio passed a mandate for AHT education in 2008²⁹; implementation has been highly variable (unpublished data). Washington did not have an established AHT primary prevention program during the study period.

The lack of a difference in the demographic or clinical characteristics of subjects before compared with during the recession indicates that the recession was a societal-level risk factor that increased risk for all. We incorrectly hypothesized that more children with AHT during the recession would show evidence of previous abuse, because cuts in Child Protective Services budgets might result in episodes of mild abuse not being investigated because of a lack of resources. The fact that half of the subjects showed evidence of previous abuse is consistent with the results of previous studies.^30,–,32 We also incorrectly hypothesized that a larger proportion of perpetrators during the recession would be male because the recent recession affected jobs traditionally held by men more than jobs traditionally held by women.³³ Finally, our hypothesis that more children would be receiving public insurance during the recession was not supported by the data. The fact that 79% of the subjects had public health insurance before the recession compared with 30% of children nationally³⁴ is consistent with data suggesting that poverty is a risk factor for physical abuse.³⁵

The lack of relationship between unemployment rates and the AHT rates might be the result of recognized limitations in US unemployment data.²³ Unemployment data, for example, do not account for workers who are underemployed, have exhausted unemployment benefits, have stopped looking for work, and/or who receive disability benefits. Although previous studies have revealed a relationship with unemployment, it is possible that the limitations in the unemployment data have become more pronounced over time because of changes in the proportion of underemployed and/or seasonal workers. It is also possible that other macroeconomic indicators (eg, foreclosure rates) might correlate with AHT rates.

This study had several limitations. It is possible that there was a selection bias such that certain hospitals would be more likely to volunteer to participate because they perceived that the rate of AHT had increased at their site. Although the study was triggered by a perceived increase in AHT in Pittsburgh, the selection of other sites was based only on whether hospitals had met the previously described criteria. Numerous hospitals were eliminated from consideration because of the presence of multiple trauma centers in the region. Dr Berger then contacted >30 other institutions to assess eligibility. The majority of sites were ineligible because of lack of a stable CPT and/or lack of available data about cases of AHT at their respective hospitals.

A second limitation relates to possible site differences in the definition of unequivocal AHT. Although it is possible that different sites defined unequivocal AHT differently, these differences would be expected to be stable across the entire study period, because the members of the CPT were stable during this time. By including only cases of unequivocal AHT, we also sought to minimize differences in interpretation.

Finally, it is possible that not every case of AHT that occurred in each encatchment region was included. Because of selection criteria for participating hospitals and our additional data collected about children evaluated at nonparticipating hospitals, we are confident that the vast majority of eligible children were included. For the few cases that were not included, we believe that they are nondifferential misclassifications across encatchment areas.