Our results show that thalassemia patients are facing an important challenge in terms of diagnosis delay. The main goals of TPP are early diagnosis of thalassemia and prevention of new cases. Despite significant improvements in the TPP in Iran, the rate of delay in diagnosis must be considered by policymakers to modify the program. Assessing factors associated with diagnosis delay might be an important way to identify how to improve the quality of thalassemia program. Accordingly, the results of our study can help policymakers in this purpose.
After the establishment of TPP in Iran, the program has been evaluated from different perspectives. The first study conducted by Samavat et al. (
14) in 2004, and another one in 2007 (
15) showed a significant success in decreasing the rate of thalassemia newborns, which was further validated by other studies (
16-
18). Khorasani et al. (
16) in a study to evaluate the success of the program concluded that the TPP has significantly reduced the financial burden upon thalassemic patients and their families. On the other hand, some other studies have reported program weaknesses. Findings of a study to evaluate the Iranian TPP during 2007-2009 revealed that the program should be revised in at-risk provinces especially in Sistan-Baluchestan and Kohkiluyeh Boyer-Ahmad (
19). In addition, the delay in registration of thalassemic patients in the disease registration system as a limitation of the program has been pointed in previous studies (
9,
17). Nevertheless, no similar study was found on the delayed diagnosis in thalassemia in Iran or other countries. As far as we know, this is the first study in this regard worldwide. On the other hand, we suppose that policymakers probably think that the diagnosis testing such as PND can detect all of the disease cases. However, there are numerous patient- and health system-related factors associated with the delay in diagnosis.
We found that 64.9% of patients had delayed diagnosis. The high proportion (41.4%) of them had delay less than 12 months. On the other hand, this time, i.e. 12 months after birth, is the time for immunization of children. It, therefore, is concurrent with the immunization program which was launched in Iran in 1984 (
20). This issue could explain the shorter mean delay in the birth cohort of 1981 - 1990, 1991 - 2000, and 2001 to the present compared to the birth cohort of 1980 and before. Despite a significant decrease in the mean delay, ordinal logistic regression showed a positive linear trend in birth cohorts which was associated with delay in diagnosis. This finding suggests that there is still a major problem in the TPP.
Based on both unadjusted and adjusted ordinal logistic models, sex was an important predictor of delayed diagnosis in the patients. Gender disparity in healthcare utilization and health related factors have been widely reported (
21-
23). In some societies, for example India, gender discrimination is an important determinant of healthcare utilization such as childhood vaccination (
21). Our study revealed that the odds of delayed diagnosis were greater in girls than boys. They also had a higher mean delay compared to boys (16.0 vs. 10.9 months, P value = 0.042, respectively). Also in a few studies, significant gender-based differences of delay have been reported in presentation of childhood disorders (
24,
25).
The risk of delayed diagnosis in thalassemic patients was lower among high educated parents. Some ways could be noticed that infant health is associated with the level of parental education. For example, Wehby et al. reported that the higher parental education increased the number of prenatal care visits and decreased the risk of preterm birth (
26). Numerous previous studies have also reported a significant relationship between maternal education and infant health (
27,
28). Accordingly, since high maternal education is an important predictor of child health, expanding the health educational programs are required to improve health literacy and health knowledge of mothers. In our study, the mean delay was significantly higher among those patients who had employed mother, and ordinal logistic regression also showed a higher odds of delayed diagnosis among employed mothers than unemployed ones, but without significance. Maternal occupation may affect infant health that was also considered in several studies (
29,
30). Time, for example maternal time for receiving healthcare, is an important factor to determine well-baby care receipt (
31).
4.1. Study Limitations and Strengths
This study encountered some limitations. First, we performed a retrospective cross-sectional study and used data recorded by the registry center. Hence, we were unable to assess the quality of the recorded data. This might raise information bias. On the other hand, there are probably other factors associated with patients and healthcare system delay that could not be assessed in this study. The main strength is its novelty in reporting of delay in diagnosis with an appropriate sample size from a developing country. It may help policymakers who plan preventive programs reduce thalassemia rate.
4.2. Conclusions
A high proportion of delayed diagnosis was found. These results could explain the poor outcomes for thalassemia patients. We suggest that the PND errors and the causes of delayed diagnosis be recorded and analyzed. Educational programs for the community and revising the thalassemia prevention program are required for early detection of the disease.