The economic impact of preschool asthma and wheeze

Study design

During the course of a RCT designed to examine the impact on morbidity of providing an educational intervention and self-management plan to the parents of children aged 18months–5 yrs who had recently attended hospital with aprimary diagnosis of asthma or wheeze 14, data were collected on healthcare resource use and familial, healthcare and employment costs. Between February 1998–March 1999, 200 children were recruited to the trial from either a children's ward or the accident and emergency department of Leicester Royal Infirmary (Leicester, UK) or Booth Hall Children's Hospital (Manchester, UK). Two-thirds (67%, 134 of 200) of the sample were males and 79.5% (159 of 200) and 14% (28 of200) were of Caucasian and South Asian (Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka) origin, respectively. Of these 200 children, 110 resided in Leicestershire, for which recent population survey data are available 15, enabling estimation of the costs of wheeze in preschool children. Of this subset of 110 children, complete data on healthcare resource use and familial, healthcare and employment costs were available for 94 families and form the basis of the present report. For the 90 children in the study who attended the trial centre in Manchester, similar population survey data were not available and so they were discounted from this cost of illness evaluation.

The methods used to collect the cost data within the RCT, use of the population survey data and subsequent cost calculations are described below. The reader is referred to a previous publication for a detailed description of the RCT 14.

Collection of cost data

At the end of the trial period, the study team completed a structured interview schedule with parents to assess family-borne costs and the value of waged and nonwaged time lost as result of the family caring for their preschool child with wheeze or asthma during the previous year. The interview schedule explored the costs incurred by parents when their child was unwell with asthma according to five possible scenarios: caring for the child at home; attending the GP's surgery; attending hospital for an outpatient consultation; attending the accident and emergency department (A&E); and being cared for as an inpatient. Cost data were collected only for those scenarios encountered by each family during the previous year.

Family-borne costs

For each of the five scenarios encountered by the family, family-borne costs were calculated according to three categories: 1) cost of providing a carer to mind either the unwell child, when the child required care at home and the usual parent/carer continued to work, or other dependants, when the parent/carer accompanied the child to a consultation; 2) cost of travel calculated for either the cost of fares on public transport or, in the case of car travel, the distance of the family home from the GP's surgery or hospital with cost of car travel set at 0.3956 UK pounds (GBP)·mile⁻¹ 16, and, if the child was admitted to hospital as an inpatient, how frequently the journey to hospital was made each day; and 4) out-of–pocket expenses such as excess costs of drinks, meals, magazines, newspapers and telephone calls. For each scenario, parents were asked to recall the costs typically incurred. For inpatient stays, parents were asked to recall their costs for a typical 24-h period.

Family-borne costs incurred while caring for the unwell child at home were based only on the costs of providing a childminder, if required. Although caring for an unwell child at home may incur other family-borne costs such as extra heating, particularly during the winter months, these are difficult to determine and quantify and were omitted from the cost calculations.

Family-borne costs incurred while taking the child to the surgery were based on travelling and childminding costs alone as it was assumed that there would be few, if any, further out-of-pocket expenses, such as drinks or food, during such a relatively short time period.

For the four scenarios entailing either a GP consultation or attendance at hospital for which it was considered possible that two caregivers would adopt major care roles, costs for the primary caregiver, who was identified as spending most time with the child, and the secondary caregiver, who spent less time with the child, were determined separately.

Data were also collected on regular monthly purchases made by parents of items that they believed would relieve their child's symptoms. The purchase costs of occasional expensive items, such as vacuum cleaners and hypoallergenic bedlinen, were not included.

Data from the RCT 14 provided evidence on the number of surgery consultations and attendances at hospital made by each child. Symptom diaries provided data on the number of occasions when the unwell child was cared for at home. Trial families were asked to complete a 4-week symptom diary on three occasions during the 12-month trial period. Parents were asked to indicate when their child was unwell at home with asthma. However, the number of days when the child was unwell is an underestimate as not all of the 94 trial families completed symptom diaries. Of a possible 282 symptom diaries (94 families completing symptom diaries on three occasions), only 137 (48.5%) were successfully completed and returned.

Using these data on family-borne costs for each care scenario and the number of such events from the RCT data 14, it was possible to calculate family-borne costs for each family over a 12-month period.

Costs of time lost from waged and nonwaged employment

Time spent caring for a child who is unwell represents a loss of time that could have been spent on other activities including waged employment or nonwaged pursuits. In order to estimate the costs of time lost from waged and nonwaged employment, parents were asked, for each scenario encountered, who would usually care for the child under such circumstances and whether this would require them taking time off from paid employment. Parents were then asked to estimate the typical duration of each event, based on experience, including travelling time to and from the surgery or hospital. As for family-borne costs, for each of the four scenarios entailing either a GP consultation or attendance at hospital, parents were asked about the time costs incurred by both the principal and secondary caregiver.

When the child was unwell at home, the costs of lost nonwaged employment were assumed to be zero since a disease such as childhood asthma is unlikely to require intensive input from carers except for short periods, e.g. during drug administration. Likewise, estimates of lost waged time were based on those of just one parent as it was considered likely that the child would require the care of only one caregiver at a time. Time lost from waged employment when caring for the child at home was assessed using symptom diary data, which indicated when the unwell child was cared for at home.

The value of time lost from paid employment was estimated using mean wages for male and female workers in the East Midlands, the region in which Leicestershire is situated, for April 1999 17, 18. This method results in a mean weekly gross wage of 398.30 GBP for 42.1 h (9.46 GBP·h⁻¹) for a male and 286.70 GBP for 37.8 h (7.58 GBP·h⁻¹) for a female. Costs of nonwaged time can be represented as the opportunity costs of tasks that would otherwise have been carried out, e.g. household chores 19, 20. This was estimated using the mean wage for a local authority home-care worker, i.e. 5.11 GBP·h⁻¹ 21.

Using these mean wages, parental estimates of time spent for each scenario and RCT data 14 from symptom diaries and the number of GP consultations and attendances at hospital, it was possible to calculate the value of lost waged and nonwaged employment for each family over a 12-month period.

It was assumed that family-borne waged and nonwaged costs incurred during visits to the surgery would be the same whether the consultation was with the GP or practice nurse and thus costs were calculated using the sum of all surgery consultations.

Similarly, costs were calculated only for those consultations requiring the child to attend the surgery and not for GP consultations at home.

Health-service costs

Health-service costs refer to the direct medical costs of providing primary and secondary care and medication. These costs were obtained from various sources and were used to calculate the total health costs of the 94 trial families.

A primary care consultation with a GP was costed at 16 GBP for a surgery consultation and 49 GBP for a home visit 21. A consultation with the practice nurse at the surgery was costed at 9.14 GBP 21.

Secondary care costs were obtained from the finance department of Leicester Royal Infirmary. An outpatient appointment cost 113 GBP for a new patient and 56 GBP for an existing patient. As it was not possible to determine whether the first appointment attended during the 12-month trial period was as a new or existing patient, a conservative estimate was made, assuming that all outpatient appointments were for existing patients. An emergency visit to A&E costs 35 GBP. The cost of an inpatient stay was estimated using Healthcare Resource Group prices, which are based on several factors including length of stay and primary diagnosis 22.

The cost of drugs prescribed to the children was taken from a published source 23. The costs of inpatient and discharge drugs prescribed following any attendance at hospital during the 12-month trial period were not included in the calculations as this would have required examination of the hospital notes of all 94 children.

Use of healthcare resources

As part of the RCT, the numbers of GP and practice-nurse consultations, including the number of home visits, made during the 12-month trial period were obtained from the patient's GP records. From these records, prescription data, including the type of medication and the dosage for each child in the 12-month trial period, were also obtained. The number of visits made to the hospital for outpatient appointments or to A&E and the number of days spent as an inpatient were determined from case notes and hospital records.

Using the health-service costs and data on healthcare resources used by the 94 families, the total and mean costs of providing healthcare to all the families over a 12-month period were calculated.

Use of population survey data

Data from the RCT 14, a population survey 15 and a personal communication (C. Kuehni, Dept of Social and Preventive Medicine, University of Bern, Bern, Switzerland, September 20, 2001) were used to estimate morbidity due to asthma and wheeze in the preschool population of Leicestershire.

During the 13 months in which recruitment to the RCT 14 took place, a total of 383 different children aged 18 months–5 yrs were either admitted to Leicester Royal Infirmary (the only secondary care centre in the county) as an inpatient or attended A&E as a first attendance. Therefore, it can be estimated that during a 12-month period, 354 different preschool children aged 18 months to 5 yrs within Leicestershire attended hospital with a primary diagnosis of asthma or wheeze. Assuming that hospital admission rates for those aged 12–18 months are the same as for those aged 18 months–5 yrs, it is estimated that 404 different preschool children aged 1–5 yrs attended hospital in Leicestershire with a primary diagnosis of asthma or wheeze, representing 0.88% (404 of 46,160) of the total Leicestershire population aged 1–5 yrs (A. Davies, Leicester City West Primary Care Trust, Leicester, UK, personal communication dated April 10, 2000).

Data collected via a postal questionnaire sent to the parents of >3,410 Leicestershire children in 1998 (C. Kuehni, personal communication dated September 20, 2001) showed that 24.6% (827 of 3,358) of preschool children aged 1–5 yrs had reported wheeze or asthma during the previous 12 months 15. Of those children reporting wheeze, 93.5% (773 of 827) had consulted their GP with symptoms 15; this represents 23.0% (773 of 3,358) of the total preschool population aged 1–5 yrs. Of those children who consulted their GP, the greatest number of children, 43.2% (331 of 766), consulted their GP two or three times during the year, with 58.2% (446 of 766) receiving treatment and 41.8% (320 of 766) not receiving treatment (seven nonrespondents).

Estimates of population morbidity in the UK

Estimates of population morbidity in Leicestershire were used to estimate the population morbidity of the UK preschool population.

In 1998, 6.2% (3.67 million) of the UK population of 59.2 million were aged <5 yrs 17. Accordingly, it is estimated that 2.94 million (0.8 × 3.67 million) were aged 1–5 yrs. If, in 1998, 24.6% of these wheezed during a 12-month period, estimates suggest that 0.72 million children in the UK aged 1–5 yrs wheezed. Furthermore, if 0.88% of preschool children attend hospital in 1 yr due to asthma or wheeze, then, potentially, in 1998 in the UK, 25,850 children aged 1–5 yrs attended hospital for wheeze or asthma.

The above figures are used in the calculations of preschool asthma or wheeze-related health and societal costs. The estimates of population morbidity presented here compare favourably with other data sources that report that ∼22% of preschool children reported wheeze in the previous 12 months 24 albeit higher than the reported wheeze of older children 8.

Cost calculations

Estimates of health-service costs, family-borne costs, and the value of waged and nonwaged time for the 0.88% of the UK preschool population admitted to secondary care were based on mean healthcare costs from the present sample. This assumes that healthcare-resource use in this sample approximates to that of all families in the UK with a child hospitalised due to wheezing.

To calculate healthcare costs for those children who attended only primary care for wheeze, the present sample healthcare-cost estimates were not thought to be adequately representative. The mean number of GP consultations for wheeze or cough in the sample children was 4.8 14. Data from the population survey showed that, of the 3,410 respondents, 1,283 (37.6%) were South Asians, who were found to consult their GP more frequently than Caucasians (e.g. mean number of GP consultations for wheeze or cough in children with current wheeze was 3.0 in Caucasians and 3.6 in South Asians) (C. Kuehni, personal communication dated September 20, 2001). However, in the UK as a whole, South Asians represent ∼2.5% of the population 25. Therefore, to calculate healthcare costs for those attending only primary care, estimates of the number of GP visits made by Caucasians in the population survey 15, being more representative of the UK population, were combined with the unit cost of a GP visit 21. All visits to the surgery are costed according to a consultation with the GP as no data are available from the population survey on consultations with the practice nurse. No information was available regarding prescription costs for inhaler treatment for those attending only primary care and, therefore, mean prescription costs from the sample of 94 families were used.

The distribution of the National Health Service (NHS) cost data was skewed with relatively few children contributing excessively to the total costs. However, service providers are concerned with the mean cost of an event as this allows direct calculation of costs for samples of different size. Therefore, costs are presented as mean±sd and median (95% confidence interval).

Data from the 94 trial children

Data showed that they had a mean of 5.4 consultations with their GP or practice nurse during the 12-month follow-up period. There were 52 (55.3%) reported episodes managed at home, 11 (11.8%) attendances at A&E due to asthma or wheeze and 29 (30.9%) were admitted to hospital (for a total of 61days) (table 1⇓).

Costs of inpatient stays represented 56.8% of total healthcare costs (fig. 1⇓).

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Fig. 1.—

Distribution of healthcare costs for preschool children in the UK during a 12-month period following attendance at hospital for wheeze or asthma (□: inpatient; └: general practitioner; ┘: outpatient; : prescription; : accident and emergency department; : practice nurse).

Family-borne costs and healthcare costs represent 5.6 and 76.3%, respectively, of total costs (fig. 2⇓).

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Fig. 2.—

Distribution of all costs incurred caring for preschool children in the UK during a 12-month period following attendance at hospital for wheeze or asthma (□: healthcare; └: family-borne; ┘: unwaged time lost; : waged time lost).

The mean family-borne costs of looking after a preschool child following attendance or admission to hospital was 31.86±43.27 GBP·yr⁻¹, of which almost one-half was due tothe cost of regular purchases such as cough medicines (table 1⇑).

When the families cared for their unwell child at home, no direct costs were documented; although three families had to arrange a childminder for the child while they went to work, none had to pay for this help. The mean daily cost to families when their child was in hospital was 10.08±39.30 GBP (table 1⇑).

The costs of time lost from waged and nonwaged employment were similar (table 2⇓), representing 18% of overall costs (fig. 2⇑).

As might be expected forthe trial population, inpatient costs constitute the greatest proportion of health-service costs (56.8%), whereas drug costs represent 6.2% of total healthcare costs (fig. 1⇑).

In the UK as a whole

It is estimated that, in the 12 months following attendance at hospital for wheeze or asthma, children aged 1–5 yrs have 124,400 GP consultations, costing the health service 2.66 million GBP and make 21,500 outpatient department visits costing 1.20 million GBP (table 2⇑). These children spend 16,800 bed-days in hospital costing 6.29 million GBP and make 3,100 emergency visits to A&E costing 0.11 million GBP (table 2⇑). The total healthcare costs for this group of children are estimated at 11.08 million GBP.

It is estimated that those attending primary care only and receiving treatment make 1.40 million visits to the GP costing 22.36 million GBP, whereas those not receiving treatment have 0.58 million consultations with the GP costing 9.23 million GBP (table 3⇓).

In the UK as a whole, families spent an estimated 0.82 million GBP providing care to a child admitted to hospital with wheeze within the last 12 months (table 2⇑). The cost to society as a whole for this group of children amounted to 14.53 million GBP.

Prescription costs amount to 10.8 million GBP (table 3⇑). Consequently, the total healthcare costs for all 1–5-yr-olds in the UK reporting wheeze are estimated to be 52.75 million GBP (1998/1999 figures).