The Children with Special Health Care Needs (CSHCN) screener includes five question sets. Each question set asks whether the child has some type of elevated or unusual need for services, or a limitation in activity. Follow-up questions determine whether the service need or limitation is due to a chronic health condition. A child who meets any of the five criteria is identified as having a special health need. Following the organizational structure of the CSHCN screener, I selected survey items from the NHIS and responses that would designate children meeting each of the five screening criteria. An algorithm was structured to identify children who met any of the criteria.
The screening question content areas, the individual NHIS questions, and the prevalence of the various indicators used in the algorithm are described in . A relatively large proportion of children (10.8 percent) were reported to have a health problem for which they have taken prescription medications for at least three months. Smaller percentages reported that the child had seen or talked to a physical, occupational, respiratory, or speech therapist or audiologist in the past year (4.5 percent); and 5.2 percent reported that the child had seen or talked to a mental health provider.
Children with Special Health Care Needs Screener Criteria and Elements Selected from the NHIS to Operationalize CSHCN Screen
Several measures on the NHIS were considered to identify children with elevated or unusual service use. These include numbers of visits to health professionals, overnight hospital stays, home care visits, hospital emergency room visits, and surgical procedures, all in the past 12 months, whether the child currently receives special education or early intervention services, and whether the child has an impairment that requires use of special equipment. The number of surgical procedures was not used in the algorithm because procedures to repair minor defects (e.g., hernia repair) or otolaryngology procedures are very common in children. Likewise, the number of hospital emergency room visits was not used, because high emergency room use may represent poor access to primary care, rather than the consequence of a chronic condition.
Thresholds for the number of office visits, home care visits, and hospital stays were established after examining the population distributions; levels were selected to capture approximately 10 percent or fewer children. The 10 percent target is somewhat arbitrary; the MCHB definition does not provide guidance as to what constitutes a need for services “beyond that required by children generally.” Approximately 2.7 percent of children had an overnight stay not related to birth, and only 1 percent of children had any home care visit. The presence of either was used as an indicator for elevated service use. The choice of a threshold for physician office visits was constrained because the visit data are reported in ranges. An estimated 7.2 percent of children had 10 or more visits. The next lowest threshold available was “four or more visits,” which captured 32.2 percent of children, too large a group for the 10 percent target.
One of the limitations of the NHIS measures of elevated service use, compared with the CSHCN screener, is that they do not capture children who need, but may not receive an elevated level of services. The NHIS includes questions about unmet need for a variety of services. In sensitivity analyses I included unmet medical, prescription drug, and mental health need in the algorithm to capture CSHCN who may have limited access to care.
Overall, 6.5 percent of children are reported to be limited in some way due to a physical, mental, or emotional problem. Relatively few children (0.4 percent) have reported limitations in activities of daily living and only 1.6 percent report mobility impairments.
Most of the available NHIS questions concerning service use do not explicitly link to the presence of a chronic health condition, but the algorithm created to identify CSHCN requires that the child be reported to have a chronic condition. The information on chronic health conditions comes from two sources. For children reported to have a limitation of activity, information is collected on the NHIS concerning the type and duration of the condition that causes the limitation. The types of conditions identified include vision problems, hearing problems, speech problems, asthma or breathing prob-lems, birth defects, injuries, mental retardation, other developmental delay, behavioral conditions, bone or muscle conditions, epilepsy, or up to two otherwise unspecified conditions. Information on duration was used to identify those chronic conditions that had been present for at least 12 months or since birth.
The NHIS also includes questions concerning the presence of a series of medical conditions. The questions are asked in two ways: whether a physician or health provider ever told the parent that the child had a specific chronic condition, and whether the parent reports that the child had selected conditions or symptoms in the past 12 months. The first group of “diagnosed” conditions includes attention deficit disorder (ADD), mental retardation, other developmental delay, autism, Downs syndrome, cerebral palsy, muscular dystrophy, sickle cell anemia, diabetes, arthritis, congenital or other heart problems, and asthma. The asthma question is refined by follow-up questions concerning the presence of an asthma attack, and the need for an emergency room visit in the past 12 months. The group of parent-reported symptoms or conditions includes seizure, respiratory allergies, eczema or skin allergies, food or digestive allergies, frequent diarrhea or colitis, anemia, or frequent headaches. An indicator was created for children reported to be “unhappy, sad, or depressed” often during the past six months as a proxy measure for children with depression or anxiety. Very low birth weight (under 1,500 gm) children under age two were identified due to their elevated need for monitoring, even in the absence of reported limitations or medical conditions.
Using the individual measures from the two sources, I created a “limited” and a “comprehensive” indicator for chronic conditions. The comprehensive indicator includes any chronic condition associated with a limitation of activity, any of the conditions diagnosed by a health professional, with the condition that the child must have had active asthma symptoms within the past year, those symptoms or conditions reported by parents in the past 12 months, the childhood depression indicator, and the children with very low birth weight. The limited condition indicator excludes those symptoms or conditions reported solely by parents because some of the conditions tend to be less serious, and the duration is not reported.
Prevalence estimates for the individual conditions and for the various summary measures of chronic conditions are provided in . The comprehensive condition measure captures more than 40 percent of all children, suggesting that it captures a broad array of children with conditions that vary with respect to seriousness and duration. The limited measure captures almost 18 percent of children. An emotional, developmental, or behavioral condition is reported for 10.6 percent of children.
Prevalence of Reported Chronic Health Problems among Children
A general limitation to use of household survey data to identify children with special health care needs is the reliance on parent or child report of medical conditions, activity limitations, and use of health care services. However, all of the national estimates of the prevalence of CSHCN rely on self-report. There are two additional limitations that are specific to this NHIS algorithm. First, some children with chronic medical conditions may not be captured if their condition does not limit activities and is not included in the battery of questions concerning medical conditions. This limitation might cause the algorithm to understate the prevalence of CSHCN by a small amount. Second, there is not an explicit linkage between questions about service use and medical conditions in most cases. It is possible that a child might have elevated service use associated with one or more acute conditions, and also report a chronic condition that is not associated with either a limitation of activity or elevated service use. This child would be identified by the algorithm as having a special health need, resulting in an overstatement of the prevalence of CSHCN. Although it is not possible to quantify the magnitude of error associated with this limitation given the current data, the error acts in the opposite direction of the first limitation described and is expected to be small in magnitude.
Measuring Characteristics of Children and Families
Measures of age, race and ethnicity, gender, family structure, insurance coverage, and sources and amount of income are available on the person-level files of the NHIS. Records for parents and children were linked to create measures of family structure, parent education, and poverty status on the child's record. Indicators for child receipt of Temporary Assistance for Needy Families (TANF), current enrollment in Medicaid or SCHIP, and for any current insurance coverage were created.
Weighted means and proportions were calculated using pooled data for 1999–2000. Sample proportions were also calculated for selected variables for 1997 and for 2000, and comparisons were made across the two years. Standard errors were adjusted for the NHIS complex survey design. All analyses were performed using Stata software, version 8.