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I congratulate Dr Marrero and colleagues on the excellent paper published recently in Thorax about their experience with tuberculosis in Cuba from 1962 to 19971and consider that many developing countries, together with some developed countries like ours, should imitate their methods and their political commitment to a national tuberculosis programme. However, I wish to raise some questions and to comment on some points.
I was pleasantly surprised at the considerable improvement in the case finding from 1993 onwards. From 1983 to 1993 the number of new cases of tuberculosis per year ranged from 514 to 789 with 85.5–91% smear positive patients (similar to the period since 1962). In 1994 there was a sudden increase to 1617 cases (from 789 cases in 1993) with a significant decrease in the percentage of smear positive patients to 56% (from 91% in 1993). This sharp fall was maintained up to 1997. The authors consider that the expansion of the case definition by the World Health Organization in 1994 to include “clinical symptoms and radiological features suggestive of tuberculosis but with negative sputum smears and negative culture” may have been a significant factor, but in my opinion this is already included in the definition “pulmonary tuberculosis with negative sputum smear and positive or negative culture”. I would argue that improved case finding as a result of the evident increase in the number of patients with respiratory symptoms studied (from 62 370 in 1993 to 179 493 in 1997) and in the number of contacts per case of tuberculosis studied (from 4.8 in 1993 to 12.5 in 1997) led to the sudden decrease in the rate of smear negative patients. This decrease is more appropriate and credible for a country in which the distribution of tuberculosis cases by age is similar to that found in industrialised nations,2 3 a fact that Dr Marreroet al point out in their paper.
authors′ reply We appreciate the comments by Dr Garcia-Zamalloa on our paper on the control of tuberculosis in Cuba. We stated in the discussion that “better case finding and the change in the case definition may explain the increase in the period 1992–1994”. The improvement in case finding is related to the comments by Dr Garcia-Zamalloa concerning the better detection of patients with respiratory symptoms and contacts per case studied. However, in 1994 there was a change in the case definition in Cuba because, before this year, patients with clinical symptoms and radiological features suggestive of tuberculosis who were smear and culture negative were not included in the register of the programme. This change and the better case finding also influenced the decrease in the percentage of smear positive cases.