Factors such as diagnosis in the emergency department, advanced age, and visits < 30 days to outpatient care were associated with an increased risk of mortality.
However, the study found that treatment with statins was associated with a lowered risk for both emergency department visits/hospitalization and mortality.
In our study, 47% of individuals maintained HbA1c levels above 52 mmol/mol during follow-up, indicating inadequate glucose control, which did not affect emergency department visits or hospitalization.
In this investigation, there was an association between enhanced mortality risk and the monitoring and regulation of HbA1c, LDL-cholesterol, and renal impairment.
Our study revealed that individuals diagnosed in the emergency department faced an elevated risk of hospitalization and emergency department visits during the study period.
In this retrospective study of individuals with T2D and a new CVD diagnosis, the majority of T2D individuals initially received their new CVD diagnosis during inpatient care. Subsequently, the follow-up was primarily conducted in primary care. The overall mortality rate in the study group was 24%, with the highest mortality rate observed among those diagnosed either during inpatient care or in the emergency department. Factors such as diagnosis in the emergency department, advanced age, and visits < 30 days to outpatient care were associated with an increased risk of mortality. However, the study found that treatment with statins was associated with a lowered risk for both emergency department visits/hospitalization and mortality. Blood pressure higher than 100 mm Hg was associated with a lowered risk for mortality.
Lowering HbA1c levels, particularly achieving near-normal levels (HbA1c < 53 mmol/mol), is associated with reduced microvascular complications [23, 24]. However, the impact on macrovascular disease is complex [25]. In our study, 47% of individuals maintained HbA1c levels above 52 mmol/mol during follow-up, indicating inadequate glucose control, which did not affect emergency department visits or hospitalization. This aligns with the definition of CVD events as macrovascular [26]. Nevertheless, it had a more detrimental effect on retinopathy and diabetic nephropathy risks. The 10-year follow-up of the UKPDS post-trial study revealed that the earlier period of tight blood pressure control did not show sustained benefits in terms of macrovascular events, mortality, or microvascular complications [26]. In our one-year study, the impact of blood pressure control on cardiovascular events was aligned with expectations. Importantly, low blood pressure emerges as a marker associated with an adverse prognosis for mortality. Prior studies have established an association between elevated LDL-cholesterol levels and increased rates of cardiovascular events and mortality [27, 28]. Our study indicates an association between high LDL-cholesterol and increased mortality risk, although the evidence is less conclusive regarding the risk of a cardiovascular event, possibly due to the study’s relatively short duration in this context. In this investigation, there was an association between enhanced mortality risk and the monitoring and regulation of HbA1c, LDL-cholesterol, and renal impairment. Remarkably, good control of these variables has been achieved to a notable extent, considering the 24% mortality rate observed among individuals over the study duration. Individuals subjected to treatment with metformin, SGLT-2 inhibitors, and statins exhibit a diminished mortality risk. However, establishing a similar effect concerning the risk of hospitalization or emergency department event was lacking.
Prior research has indicated that the combination of T2D and CVD indicates a higher risk of hospitalization [5, 6]. Our study supports these findings, demonstrating an average hospital stay of 6.5 days following discharge. In contrast to medical conditions that necessitate frequent hospitalization, such as heart failure, the average duration of hospitalization for heart failure is 6.6 days [19]. Regarding the follow-up visits after the onset of CVD diagnosis, our study found that the frequency of visits to the hospital’s outpatient care is relatively low, even though most cases of newly diagnosed CVD are identified during inpatient care. The primary mode of follow-up care predominantly occurs in primary care settings, which can be attributed to the common practice of monitoring T2D individuals in primary care. Our study revealed that individuals diagnosed in the emergency department faced an elevated risk of hospitalization and emergency department visits during the study period. Moreover, increased age and early re-visits to hospital outpatient care after being diagnosed with CVD were associated with a higher risk of experiencing serious adverse events. The likelihood of early re-visits to the hospital’s outpatient department leading to increased hospitalization or emergency department visits may be attributed to the severity of CVD in these individuals.
Previous studies have indicated an elevated mortality rate in individuals with T2D and CVD compared to the control group [4, 7]. This current study also affirms an elevated mortality rate of 24% in individuals with both T2D and CVD. This mortality rate is notably higher than the 17% reported in a prior study, with the disparity likely attributed to the inclusion of individuals at the onset of CVD in the present study. The study’s findings emphasize that mortality rates were notably elevated, especially within the initial two weeks and among individuals diagnosed in the emergency department. A similar pattern with a high mortality rate was previously reported in a population of patients with heart failure [20]. This underscores the substantial CVD risks associated with T2D and the importance of precise and relatively intensive monitoring of these individuals. Factors associated with increased mortality are increasing age and high cholesterol levels, while in this study it was important where the patient received the CVD diagnosis. In contrast, treatment with metformin, SGLT-2 antagonists and statins is associated with reduced mortality risk. Likewise, follow-up in primary care within 31 days after CVD diagnosis was established with an associated reduced risk of mortality. Consequently, prioritizing the follow-up of T2D individuals in primary care in Sweden is warranted, and it is reasonable to expect that primary care bears a responsibility for monitoring critical risk factors.
Strengths and limitations
This study has the following strengths: large sample size, data were based on RHIP which has good quality and complete information on the medications used and biomarkers. However, there are some limitations. It has been possible to examine the duration of diabetes, but since the lookback period only extended to 2011, this variable was not assessed to be reliable. It is likely that individuals with T2D have had the diagnosis for a significantly longer time, which would significantly affect the duration times. There is a lack of information on other potential confounding factors, for example, socioeconomic status. The study encompassed a total of 1759 participants, a figure that may be considered modest in size in certain contexts. Additionally, the study used Cox regression analysis with a substantial number of variables - a factor that could be viewed as a limitation.
In the study, the need for cardiology interventions was not recorded or investigated, which is a factor that should affect the need for readmission, visits to the emergency department and follow-up. As reliable data have not been able to be compiled, this is not included in the analyses. Given that this was a retrospective population-based study, it was not feasible to arrive at causal conclusions. Future prospective studies are needed to make causal conclusions about the observed associations.
