[Tuberculosis in the patients undergoing haemodialysis in Japan, 1996]

We conducted a questionnaire survey on patients undergoing haemodialysis about the present situation of tuberculous incidence. They are immunocompromised hosts and are said to be at high risk of developing tuberculosis in many reports. (1) DESIGN Of the 167,192 patients on haemodialysis registered on December 31, 1996 in Japan, 71,411 patients were available for the questionnaire survey. Of the 2,893 hospitals used as the study subjects, 1,108 hospitals gave satisfactory replies. Of them, 141 hospitals reported that they had patients with tuberculosis in 1996, and 79 cases were collected by the detailed survey on tuberculosis patients conducted later. They included 45 male cases, 34 female cases for tuberculosis of all forms, 28 male cases, 15 female cases for pulmonary tuberculosis (PTB), 13 male cases, 4 female cases for tuberculosis bacilli positive pulmonary tuberculosis (TB positive PTB), and 17 male cases, 19 female cases for extrapulmonary tuberculosis. (2)

In tuberculosis of all forms, the number of observed patients (O) against the number of patients expected (E) was calculated, and the standardized patients ratio (O/E ratio) was computed. It was 1.55 for male, 2.79 for female and 1.99 for total. The incidence of tuberculosis haemodialysis patients was significantly higher compared with the general population (p < 0.01). As to PTB, the O/E ratio was 1.01 for male, 1.40 for female and 1.16 for total; the incidence of PTB was not significantly higher compared with the general population. With TB positive PTB, the O/E ratio was 0.96 for male, 0.80 for female and 0.97 for total, and no significant difference was found. As for extrapulmonary tuberculosis, the O/E ratio was 13.45 for male, 13.07 for female and 12.97 for total; the incidence of extrapulmonary tuberculosis in haemodialysis patients was significantly higher (p < 0.01), but it was lower than these reported in the past literature. The seventy nine cases consisted of 52 primary treatment cases, 23 retreatment cases, and 4 unknown cases. Out of 79 cases, 36 cases developed tuberculosis almost at the same time or within 1 year after undergoing haemodialysis, and thereafter it decreased gradually. Underlying diseases for haemodialysis were mainly glomerulonephritis and diabetic nephropathy. There were many patients who failed to notify to the public health centers after the diagnosis of tuberculosis was made, and it is needed to improve such a situation in the future. The prognosis of tuberculosis undergoing haemodialysis was poor. Three out of 43 patients with PTB and 2 out of 13 tuberculosis pleurisy cases died. (3)

The risk of developing PTB in patients undergoing haemodialysis was not high compared with the general population, however, the risk was much higher for extrapulmonary tuberculosis. Moreover, the treatment outcome was not satisfactory in patients with PTB and pleurisy. As patients undergoing haemodialysis have the factors which suppress the cell-mediated immunity, it is required to restudy the measures to prevent development of tuberculosis, management and treatment in the future.