This study represents a large cohort of IE from a single center. It showed that older patients with IE had common clinical symptoms, more nosocomial origin, worse oral hygiene than younger patients. The most frequent isolated pathogens in the old groups was Streptococci. Moreover, they presented more comorbidities, more atrial fibrillation as well as more severe prognosis than younger patients. Surgical therapy was less performed in older patients although the theoretical indications for surgery was clear. Those with surgical therapy had better outcome.
The clinical characteristics of older patients with infective endocarditis
According to the published researches, the clinical features in older patients were few and untypical, which often led to a delay in the diagnosis of IE. [5, 10, 11] While, Jean et al [12] found older people had a more severe clinical status than younger patients, which lead to the early diagnosis. However, the clinical presentations in old patients was not significantly different as compared with the younger patients in our study. And the time to diagnosis was not significantly different compared with the younger patients.
In accordance with previous studies, clinical characteristics varied with aging. [12-15]Older patients were more frail, which often lead to more cardiovascular and general comorbidities and complications than younger patients. In our study, the older patients presented more predisposing factors (like previous cardiac surgery history, degenerative heart disease, hypertension, diabetes and so on) contrary to younger patients who frequently presented congenital heart disease. For IE patients, comorbidities and complications increased with ageing, just like the general population.
Different to the published researches, streptococci was the most frequent isolated pathogens in the old groups in our study. This might be owing to the large number of native valve IE and community-acquired IE in old patients. According to the published researches, streptococci was more prevalent among patients with a native valve and community-acquired IE. [16] What’s more, the bad oral hygiene among old patients might be another important reason. The microtrauma caused by these everyday activities (like oral hygiene habits) has been identified to induce oral streptococcal bacteraemia. [17] Therefore, a better control for individual oral hygiene and dental status for old patients was important in reducing oral streptococcal infective endocarditis.
In our study, we found the in-hospital mortality rate and one-year mortality rate in older patients was much higher than the younger patients, which was consistent with previous reports. [3, 14, 15, 18, 19] As reported previously, older adults were prone to require complex care needs and suffer from multiple comorbidities, which made them vulnerable to health-associated exposure and poor outcomes. [14, 20-22]Besides, the lower operative rate in older patients compared with the younger in our cohort may be another important reason for the higher mortality in older patients. [7, 13, 14]
The in-hospital mortality and one-year mortality were lower in older patients in our study compared with previous studies.[5, 14, 18] Léopold Oliver et al reported that one-year mortality was higher in the ≥80-year-old group (37.3%) than in the <65-year-old group (13%) and the 65-80-year-old group (19.7%), indicating that the mortality rate increased with aging.[13] The few number of very old patients in our study (there were only 5 patients who were over 80 years old) may be an important reason. And a larger cohort for older IE patients was suggest in our region in the future.
Surgical therapy and prognosis for patients≥65 year old with infective endocarditis
Previous studies reported that older age, renal failure, prosthetic valve endocarditis, neurological deficit, and cerebral emboli were independent risk factors for one-year mortality in older patients. [4, 23]In our study we found the independent risk factors for one-year mortality were man, hemodialysis, renal insufficiency, Pitt score ≥4 ,vegetation length>30mm and surgical treatment. These events have been confirmed previously to be risk factors for mortality in IE patients.[8, 24, 25]
We observed that elder patients with surgical therapy had a lower mortality rate compared with patients not operated during the one-year follow-up. Other recent reports also reached the same conclusion. [13] Surgery was performed less frequent in older patients in our study, although the rate of patients with theoretical indications of surgery was not significantly different compared with the younger. This phenomenon was frequently presented in previous reports. [3, 26, 27] The main consideration may be the increasing risks during the perioperative period owing to the decline in organ function and the presence of comorbidities associated with aging. These factors made the choice of surgical treatment for elderly patients more difficult.
But these considerations could not prevent the old patients with surgical indications from suitable treatments in-time. There are many frailty scores to assess the physical condition of older patients, and some scores showed good reliability in the assessment of mortality independently of age. [20] Some studies have recently proven the utility of these scores for the evaluation of IE-related stroke and prognosis evaluation before cardiac surgery. [28] Therefore, surgery is appropriate in selected old patients with IE. And we suggest a more global patient evaluation and cooperation among multiple specialists to improve IE management in older populations.
Limitations
There are several limitations in our study. First, it was performed in a referral teaching hospital where most patients were transferred from other medical centers leading to long-term disease and negative blood culture results. Therefore, these results should not be generalized to other patient groups. Second, as a retrospective study, the long-term follow-up was not possible and 29 patients were lost during the one-year follow-up. Finally, the study covered a long period of time in order to keep the enough sample sizes. Changes in treatment regimens and causative organisms could affect the patient prognosis during this period. Therefore, a multiple-center prospective cohort studies conducted in our region was suggested.