Relación de la Tutela Asistencial con la figura del cuidador y la del guardador

5.7.1

Cost Per Life Gained

The results in Section 5.4.3 can be easily converted into a cost per life gained.20

I focus on the financial year 2011/12 for these calculations to prevent confounding due to between year differences in the price level and other institutional changes; this is also the year in which the UPS was conducted.

Table 5.8 shows the estimated cost per life saved based upon the results from table 5.3. Based on the total expenditure on care days provided to different groups of infants and the corresponding number of infants in that group the number of infants who would not otherwise have died with a 10% increase in expenditure is calculated. There is clearly a heterogenous effect among the different infant groups with the estimated cost per statistical life saved for very and extremely preterm infant being £1,401,679 and £637,171, respectively.

5.7.2

Cost per life year gained

To convert the above estimates into a cost per life year gained, the cost per additional life gained can be divided by the number of life years gained. I provide both discounted

20_{For the}

ninfants in the sample, a 100/npercentage point change in the mortality rate is equivalent to one death. The estimated coefficients,γ, presented in the above tables provide the relationship between

expenditure and the mortality rate. The change in expenditure required to realise a 100/npercentage point change in the mortality rate is therefore 100/γnmultiplied by the total expenditure in the sample.

and undiscounted estimates here. The key issue with this is that there are no suitable data on the life expectancies of infants admitted to neonatal units given that the survival rate of very preterm and preterm infants in the past was very low and practically negli- gible eighty years ago. One option is to use the average life expectancy for the English population today, which is 81 years (Office for National Statistics, 2013). However, infants born in poor health, such as those born at a low birth weight, have below av- erage health, education, and labour market outcomes (Black et al., 2007), which may suggest a reduced life expectancy for these infants. However, the life expectancy of an infant born today is likely to be in excess of 81 years given reductions in the infant mortality rate and improvement to public health and medical care. To avoid these is- sues, I take the average life expectancy of 81 years. This is also the strategy of Claxton et al. (2013) in their calculations.

Using the figures presented in table 5.8, the incremental costs per life year gained for the whole sample, very preterm, and extremely preterm infants are £37,099.56, £17,304.68, and £8,384.83, respectively, not taking into account any discounting. The standard discount rate for benefits used by NICE is 3.5%. Using this rate gives equiv- alent costs per life year gained of £112,087.50, £52,301.46, and £23,766.17.21

The appropriate social discount is one of the subjects of the discussion in Chapter 8.

5.7.3

Additional Costs at the Margin

The results presented in this paper suggest that any policy resulting in increased factor inputs to neonatal units, and hence unit costs, would reduce mortality among infants admitted to neonatal units. However, these infants that would have otherwise died without the policy would now generate increased expenditure owing to their require- ments for care. Importantly, these infants are likely to be those that generate relatively high levels of expenditure. Going beyond care provided on a neonatal unit, after be- ing discharged these infants will continue to generate long term costs as they require greater resources for education, healthcare, and community care than their healthy counterparts (Mangham et al., 2009). Arguably, these costs should be taken into ac-

of certain medicines when evaluated within a healthcare context. In any case, data on long term outcomes of infants admitted to neonatal are often not available given the low survival rates of these infants in the past, and, where they do survive, any results obtained from them are unlikely to be generalisable given the rapid progress of tech- nology for neonatal healthcare.

In hospital costs

The additional length of stay an infant at the margin of mortality would generate is estimated in the following way. Lettbe the time post-birth, and leth(t)be the ‘hazard’ (i.e. instantaneous probability) of discharge at timet. I estimate the conditional hazard of discharge at timetusing a Weibull survival model:

h(t|x) =αtα−1exp(−x′β) (5.2)

whereh(t|x)is the conditional hazard of discharge, xis the vector of exogenous vari- ables from equation (6.7), and β and α are parameters to be estimated. This model

can then be used to estimate the conditional expected length of stay for infanti with observed characteristicsx_i:

E(t|x=xi) =exp(−xi′β/α)Γ(α−1+1). (5.3)

whereΓ(.)is the gamma function. The estimation of the above model, by maximum

likelihood, takes into account the right-censoring due to individuals dying prior to discharge (those for whomtis not observed). The expected length of stay is then esti- mated for each infant that died in the sample, then the difference between the predicted length of stay and the time at which the infant died is calculated. I take the median dif- ference to be the expected increased length of stay resulting from an averted death

which in this case is 53 days.22

To calculate the proportion of these days that are intensive care days, model (5.2) is re-estimated fort_IC instead oft, wheret_IC is the time at which intensive care provision is ceased due to a reduction in the intensity of the care provided to either HDC or SC. The median number of additional days of intensive care that an infant who died would generate is estimated at 6.7 days.

Based upon the previous estimates of the additional length of stay and the average unit costs of care for 2011: 6.7 days of intensive care cost approximately £8,070, the remaining 46.3 days, assuming they are divided equally between HDC and SC, cost approximately £31,830.23

This gives a total of £39,990.

Post-discharge costs

In the longer term, post-discharge from a neonatal unit, preterm infants, and indeed other infants admitted to neonatal units, are at increased risk of morbidity and dis- ability (Mangham et al., 2009; Saigal and Doyle, 2008b). This creates an additional economic burden for social and community care services as well as in the healthcare sector. Mangham et al. (2009) estimate the incremental costs associated with preterm birth (birth prior to 36 weeks gestation) of surviving to 18 years of age compared to a healthy, normal term counterpart. They find that this incremental cost is £26,752, the corresponding estimates for very preterm (<33 weeks gestation) and extremely preterm (<28 weeks gestation) births were £72,222 and £110,751.24

The infants on the margin of risk of mortality are likely to be at the upper end of the post-discharge costs distribution. Indeed, 66.1% of all deaths that are recorded in the sample used in this study occurred in infants who were very preterm, and 47.6% were in extremely preterm infants despite these infants making up only 10.4% and 3.2% of the patient population, respectively (data from the NNRD). I therefore assume that the incremental post-discharge costs associated with saving a life to be between £70,000

22_{This is likely to be relatively conservative since those at the margin are the most healthy of those}

that died and are likely to have the shortest lengths of stay among those that died.

23_{The average unit cost for high dependency care for 2011 is £868.4, and for special care it is £506.4.} 24_{The figures have been inflated to 2011 GBP from the figures stated by Mangham et al. (2009) using}

of approximately £3,140,000, £1,500,000, and £750,000 per life saved for the whole sample, very preterm, and extremely preterm infants, respectively. This translates into costs per life year, assuming an 81 year life expectancy and discounting at 3.5%, of approximately £117,120, £55,950, and £27,970 for the whole sample, very preterm, and extremely preterm infants, respectively. It is emphasized once again that these figures are relatively crude.

5.7.4

Heterogeneous Effects by Unit Volume

Table 5.7 provided estimates of the effect of neonatal healthcare expenditure at the neonatal unit at the hospital of birth disaggregated by unit volume. A has been dis- cussed throughout this thesis, there are a two reasons to suspect that the effects of ex- penditure may differ between high and low volume neonatal units. In particular, high volume neonatal units may benefit from economies of scale, which would mean that an increase in expenditure would translate into greater increases in inputs to neonatal care, and high volume units may also have greater levels of specific human capital that would mean that for a given level of labour inputs the output would be greater. This latter effect of learning by doing is emphasized when considering the neonatal unit at the hospital of birth as it is the first few hours, or even the first sixty minutes—the so called Golden Hour—that may be crucial to determining the clinical outcomes of infants admitted to neonatal healthcare.

The cost per statistical life saved and the cost per life year gained, incorporating the estimates of additional costs (£140,000), are presented in table 5.9 for very preterm and extremely preterm infants. The whole sample is not included, since these estimates were not statistically significant from zero. There are clearly large differences in the estimated cost-effectiveness threshold between infants admitted to high and low vol- ume neonatal units at the hospital of birth. The estimated cost per statistical life saved for a very preterm infants admitted to a high volume neonatal unit at the hospital of

Table 5.9 Estimated cost per statistical life for infants born in 2011/12

High volume neonatal unit Low volume neonatal unit

Cost per life Life year

gained (0% discount rate) Life year gained (3.5% discount)

Cost per life Cost per life year (0% discount)

Cost per life year (3.5%

discount)

≤32+6 201,207 2,482 7,501 1,745,050 21,543 65,089

≤27+6 _{166,131 2,051 6,197 864,545 10,673 32,247} 1_{Data are taken from the sample for financial year 2011/12}

2_{The average cot day cost was £633.5}

3_{High volume was defined as being in the top quartile of neonatal units by number of care days}

provided.

4_{Figures are rounded to the nearest thousand.}

5_≤32+6_{=infants born at≤32}+6_{weeks gestation.≤26}+6_{=infants born at≤26}+6_{weeks gestation.}

birth is £201,207 compared to £1,745,050 at low volume neonatal units.