When IHD was recorded as UC, several diseases were the most frequently associated causes of death, including AMI, AH, CIHD, HF, and DM. In contrast, when IHD was cited as the associated cause of death, AMI, DM, CIHD, COPD, and stroke were the most frequent UCs. The magnitude of these associations varied by gender and geographic region.

The results of the present study showed that AMI was the most frequently cited cause of death when IHD was recorded as one of UC or MC, as previously demonstrated. [12]. The most frequently associated causes other than AMI were AH, CIHD, HF, and DM, which had a similar distribution between men and women. Specifically, the most frequently associated causes of death between men and women were DEP in men and DM and AH in women. The relevance of AH as a relevant cause of CVD was pointed out by Villela et al.. A 2018 Brazilian study and Santo et al. A 2011 study on the association between cerebrovascular disease and AH concluded that blood pressure control is associated with reduced IHD and cerebrovascular disease mortality. [9, 20, 21]

The importance of DM as an associated cause when IHD is listed as UC was reported in a 2015 Italian study.Federi et al.. The authors observed that when analyzing DM listed in any lineage of DC, DM was listed up to 5 times more frequently compared to this cause of death listed only as UC . [5]; this finding is consistent with previous publications showing that DM is underreported when analysis is limited to UC. [22, 23]. American study by Quinone et al..Similar results were observed in IHD, particularly among women and young people. [6].

In the analysis by geographic region in this study, AH was most frequently listed in the northern region. These data support the findings of Ishitani et al..demonstrated that references to AH increased significantly when the analysis considered AH rather than UC as the relevant cause of death. [3]. The high number of references to GC reflects the incompleteness of DC, which hinders the analysis of mortality in Brazil. Using 2019 Global Burden of Disease data, Johnson et al..In 2021, it stated that GC occurs frequently, is detrimental to DC analysis, and is inversely proportional to community social indicators. [24]. These codes were proportionally less frequent in the northern and northeastern regions, suggesting improved DC completion in these regions. [15, 16, 25, 26].

The UCs most frequently associated with IHD when IHD was listed in at least one line of the DC were AMI, DM, CIHD, COPD, stroke, and dyslipidemia. The most frequently mentioned UCs in this context were DM, CIHD, and Alzheimer’s disease in women, and DEP and CA in men. Of note, DM is considered one of the major cardiovascular risk factors, and the relationship between DM and IHD has been known for many years, as has the association of DM in women. [27,28,29]. The results of this study indicate that IHD may be underestimated in analyzes considering DC that only report DM as UC. The same bias has been observed when COPD, stroke, and dyslipidemia (which share similar risk factors and pathophysiology to IHD) are each reported as UC. [7, 30, 31].Similar findings were reported by Santo et al.. In a 2022 Brazilian study using data from 2000 to 2019. [32]. In an analysis by MC, the authors observed that cardiovascular disease was the most frequent cause of death associated with death from COPD as UC, and both share confounding factors such as smoking and age as important risk factors. are doing. The association between CVD and obesity has also been reported by Adair et al..In a 2020 Australian study using the MC method. The authors found increased mortality from CVD as associated causes, DM as UC, CKD, AH, and dyslipidemia, as found in the current study. [7]. Additionally, a 2004 Brazilian study suggested an association between IHD as UC and obesity, CVD, dyslipidemia, and AH. [33].

In our analysis by geographic region, we observed that ulcerative colitis and stroke were more important in the northern and northeastern regions, while dyslipidemia and obesity were mentioned proportionately more in the Midwest. . These findings support the results of a study using data from France, Italy, and the United States, which found that the number of mentions of obesity increased when using the MC method compared to the UC method. [34]. There were more mentions of Alzheimer’s disease in the Southeast and South regions. This is in line with a 2016 study analyzed by MC that suggested an increase of up to 20% in listed mental illnesses (including dementia). [35]. These data may indicate an improvement in social indicators related to dementia and an increase in life expectancy in these last two regions. [13]. CIHD and COPD predominate in the South, which has the highest rate of tobacco consumption in the country. [36]. The predominance of ChD in the Midwest region confirms data from other Brazilian studies, which show that this cause of death is underreported in DC and is one of the associated causes along with arrhythmia, heart failure, CVD, and AH. IHD has been shown to be one of them. [37, 38].

Although 2020 was a short period of analysis, COVID-19 was one of the major UC cases with IHD as an associated cause. This finding was more frequent in the northern regions. In 2020, when IHD was recorded as an associated cause, COVID-19 was frequently listed as UC. Of note, COVID-19 ranked fifth among the most relevant causes of death during this period, reiterating the importance of this disease in the poor prognosis of patients with IHD. [39, 40]. A study by the Brazilian Ministry of Health, which used the MC method to analyze the incidence of CVD when COVID-19 was listed in the UC, also observed an increase in the number of CVD deaths during this period. This finding was also more frequent in the northern region of Brazil, as reported in the present study. [41]. These data confirm the results of a 2022 Brazilian study that highlighted the importance of comorbidities in COVID-19 patients as associated causes of death, with the most cited comorbidities being DM, AH, CKD, Obesity and IHD. [42].

The fact that mortality analysis is dependent on the quality of DC completion is a limitation of this study. Because the doctor completes her DC according to her own knowledge and experience, there may be biases or errors in her DC depending on the professional’s qualifications and training. Another relevant point is that the format of DC, which is standardized around the world, is designed primarily to identify the UC of death and its course. This may deter experts from listing past illnesses or risk factors that may have influenced death, potentially compromising MC analysis of mortality. [3, 4]. Another limitation of the present study is the observational design, which precludes assessment of causal relationships.

Future research is needed to better understand the associations found in this study and to guide public health investments to reduce IHD mortality. We also need to further understand gender and geographic region differences to make investments more specific and individualized, and to produce better results.