This study demonstrates the economic burden that immigrant TB patients in the Netherlands face during their TB illness. We show that, even in a high income country where most medical costs are covered by the mandatory health insurance, immigrants with tuberculosis do have extra out of pocket expenditures. Furthermore, immigrant patients lost 81 productive days due to their illness. Costs and time loss during the pre-diagnostic period were slightly higher for patients with ETB compared to those with PTB, which is possibly due to the added investigations needed to diagnose extrapulmonary tuberculosis and exclude other pathology. Our study confirms that TB patients are from vulnerable groups, having a high unemployment rate both before their disease and even higher during disease, and a lower average income than the general population.
Out of pocket expenditures were comparable with 3% (€353/€12000) of the average annual income of the patients. These costs may be a considerable part of their disposable income after the payment of all monthly fixed costs such as rent, marginal costs (such as electricity and water) and insurances. Moreover, these costs are all faced during the time of TB disease and thus spend in a period of around 6 months. A quarter of the interviewed TB patients were asylum seekers, who often have even less money to spend. Some authors have concluded that a cost burden greater than 10% will be catastrophic for the household [15, 21]. It is debatable if this percentage can be applied to both low and high income countries. The amount of extra costs spend will depend on the available income. For example, quite a number of patients reported to spend extra money on food supplements. It can be questioned whether patients with little income will (or need to) spend costs on these additional items, when they can't pay them. Furthermore, coping strategies may have resulted in differences in expenditures between patients, but we did not assess how patients handled these extra expenditures.
Opposed to our study, earlier studies on direct and indirect costs due to TB were done in low-income countries. While the total direct and indirect costs of our study population accounted for approximately 25% of their annual income (€353+€2956/€12000*100%), the total costs accounted for a considerable higher percentage in these low-income countries [6, 11, 14, 15]. For example, a survey in Haiti estimated out of pocket expenses and lost income due to TB illness to be 76% of the average per capita income of Haitians, while a study from India showed that TB related costs accounted for 40% of the household income during TB illness [6, 14]. The differences between these studies and ours may be explained by different social background, insurance system and a higher income per inhabitant in our high-income country.
Although time loss had not affected the income of all interviewed tuberculosis patients we did express the loss of time in costs. The height of the indirect costs may therefore be an overestimation of the costs faced by the individual patient, since these costs are mostly carried by the society. In the Netherlands, the social security system provides a benefit to all inhabitants who are jobless. Furthermore, individuals who have a job and become ill, will mostly receive their regular income. However, 57% of the interviewed immigrant patients was jobless and a quarter of them attributed their unemployment to their tuberculosis illness. An additional ten percent of the employed patients reported that their household income decreased due to their TB illness. The unemployment rate among TB patients even before their disease is higher than the national unemployment rate among non-western immigrants living in the Netherlands (16%). This in turn is much higher than that among the autochthonous Dutch population (4%). Consequently, their estimated income levels differ. Although we studied the TB related costs only among immigrant patients, it can be expected that these costs will not be much different for other TB patients, since most expenditures were spent on travel and food related items. However, when expressed as a percentage of the income, these TB related expenditures will be a smaller proportion of the income among the autochthonous TB patients.
Our study had some limitations. First of all our study population, a convenience sample of TB patients of the participating centres, was not completely representative for all immigrant TB patients. We included younger patients and fewer patients with an impaired immunity. Both factors may have led to an underestimation of the cost estimates, since older patients and those who are immunocompromised may have atypical presentations of TB, delayed diagnosis and more complex treatment needing more medical attention during follow-up. Secondly, many of the interviewed immigrants were unable to speak Dutch or English. This made it sometimes difficult to obtain reliable information, but on the basis of a face-to-face interview and with the aid of a translator the interviewers were still able to obtain detailed information about the patient costs. Face-to-face interviews are a good method to obtain detailed information from the past and diminish recall bias [22].
Lastly, we did not ask for the exact income details. In other studies the Gross National Product (GNP) and data from surveys by National Statistics Office were used [6, 12]. The average income we used in this study may be underestimated since we did not know the maximum income in the highest income category. If so, this will have resulted in an underestimation of the indirect costs, and have led to an overestimation of the relative direct costs expressed as a percentage of the average income.