In total, 363 AI patients were found, and 327 of these fulfilled the inclusion criteria. Two-hundred-ninety-eight of these patients were found to have one or more CVR factors. However, in 28 patients the risk factors were not sufficiently assessed, meaning they did not have any data for one or more risk factors. We found the following CVR factors: arterial hypertension, arteriosclerosis, coronary heart disease, peripheral artery disease, stroke, diabetes mellitus, hyperlipoproteinemia, hyperuricemia, obesity, sleep apnea syndrome, coagulation disorder, aneurysm, smoking, positive family history for the conditions mentioned above, as well as elevated values of lipids, uric acid, HbA1c, BMI or blood pressure. In total we identified 27 risk factors.
Risk factors
Only one patient did not have any risk factors. Most AI patients (n = 298) were found to have at least one risk factor (91%).
Between the three participating locations, there were significant differences regarding the evaluation of CVR factors.
On average, the patients in Hamburg were found to have about ten missing risk factors, whereas in Bremen about two factors were missing, and in Leer approximately three. There was a significant difference between Hamburg and Leer (p < 0.001) and Hamburg and Bremen (p < 0.001).
Arterial Hypertension
Elevated blood pressure (BP) was the leading global contributor to premature death in 2015 and is above all related to cardiovascular events such as stroke, myocardial infarction, heart failure, peripheral artery disease, and end-stage renal disease [16, 17]. Hypertension is defined as office systolic BP values > 140 mmHg and/or diastolic BP values > 90 mmHg [18].
In 91 patients (27.8%) arterial hypertension was documented with 44% (n = 40) of them still having a higher BP in one measurement. Almost half of the AI patients with known hypertension showed normal or low BP (n = 46) and five patients had no documented BP (5.5%) at all.
In patients, classified as not having arterial hypertension (n = 236), interestingly 21.6% showed elevated BP (n = 51). For 168 patients normal or low BP was documented (71.2%). Similar to patients with known arterial hypertension, a relevant proportion of this patient group (7.2%) did not provide any BP value (n = 17).
Concerning medication, three-quarters of the AI patients with known hypertension did not take any antihypertensive drugs according to the medical records. Furthermore, in patients who currently demonstrated high BP measurements, there were 65.9% who did not take any antihypertensive medication. Antihypertensive dose adjusting was performed by the treating family physicians in almost all cases.
Obesity
Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. Obesity is a body mass index (BMI) greater than or equal to 30 [19]. Typical complications comprise type 2 diabetes, hypertension, fatty liver disease, and obstructive sleep apnea [20].
In total, 163 patients were overweight or obese. The threshold for obesity was reached by 78 of the AI patients with 13 having a BMI of 40 or higher.
About 80% of all AI patients with a documented diagnosis of obesity had an elevated BMI (n = 91), but only 60.3% were in fact obese. However, 17 of these cases (15.3%) had no documented BMI at all. Three of the patients with documented diagnosis of obesity had BMI values in the normal range (almost 3%).
Surprisingly, 5% of all AI patients who were not classified as suffering from obesity, were in fact obese (n = 11). Only 36.1% of this patient group had BMI values in the normal range (n = 78). The threshold for overweight was reached by 72 patients (33.3%). In 66 cases weight measurements were missing (30.6%). No weight measurements were documented for 66 patients (30.6%).
Patients with elevated BMI were often found to have more than one CVR factor. Merely five of these patients had elevated BMI as the only risk factor. Fifty-three of these patients were also known to have arterial hypertension (33%). Ninety-one patients with elevated BMI showed increased lipid levels (56%) as well.
Diabetes mellitus
The 48 mmol/mol (6.5%) HbA1c threshold was used to monitor blood glucose. Target HbA1c levels for patients with type 1 diabetes mellitus (T1DM) were between 6.5 and 7.5% [21]. The target levels for type 2 diabetes mellitus (T2DM) were recently defined individually between 6.5 and 8.5% [22]. For this study, we used the 7.5% threshold for both types. Typical complications of diabetes mellitus (DM) include cardiovascular, renal, peripheral vascular, ophthalmic, hepatic, or neurological diseases [23].
Although 46 patients suffered from DM, more than 1/4 (n = 12) still had increased HbA1c values.
No DM was documented for 281 patients. However, in 17.5% of these cases, an elevated HbA1c was found (n = 49). The majority had prediabetes, only in one case the threshold for DM was reached.
Only four of the diabetic patients took antidiabetics. There were eleven patients with known DM still having HbA1c over 7.5% who did not take any antidiabetic medication. Interestingly, there were also four patients without known DM and no data for HbA1c who did take antidiabetic drugs.
Hyperlipidemia
Hyperlipidemia is known to be an important CVR factor [24]. The most important subgroup is LDL cholesterol as it is the major risk factor in the formation of atherosclerotic plaques [24]. Triglycerides act as a predictive marker for cardiovascular events [25]. The role of Lp(a) has become more important over the last few years; it is considered to be an independent risk factor for CVD [26, 27].
Concerning hyperlipidemia, about 50% of all AI patients had at least one elevated lipid level (n = 165). Only three patients demonstrated lipids in the normal range in each subgroup (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, and Lp(a)). Hundred-fifty of all AI patients were not adequately assessed, meaning that at least one value was unavailable. However, the existing lipid levels were normal. Out of the 165 patients with at least one elevated lipid, only 55 had documented hyperlipidemia. Eighteen patients with known hyperlipidemia had not been screened for elevated lipids (23.7%).
Only 17% of AI patients had data for Lipoprotein a (Lp(a)). Surprisingly no AI patient in Leer and only nine AI patients in Bremen had data for Lp(a).
In total, 126 patients had elevated total cholesterol levels (38.5%). There were six patients with data for total cholesterol but no further evaluation of the subgroups. In addition to elevated cholesterol levels, 53 AI patients also exhibited high values for LDL cholesterol.
Surprisingly, only 18 patients with known hyperlipidemia took lipid-lowering agents (23.7%). Moreover, in patients with at least one elevated lipid level, only 18.2% were taking lipid-lowering agents (n = 30).
Hyperuricemia
Hyperuricemia is closely related to CVD with higher levels of uric acid (UA) being a risk for CVD [28]. It is defined as an elevation of serum UA (> 6 mg/dL in women and > 7 mg/dL in men) [29]. We used the 5.7 mg/dL threshold as this was the laboratory reference. The underlying mechanisms of the increase in CVR are still not completely understood and are discussed controversially [30].
Only 21 of the AI patients were known to suffer from hyperuricemia (6%). Of these patients, five did not have data for uric acid (24%).
In 306 AI patients, no hyperuricemia was known. Though, 37 of these patients demonstrated elevated UA (12.1%). A big proportion (53.6%) did not have any measurements for UA (n = 164).
Unexpectedly, no patient with known hyperuricemia took uricostatic drugs but seven of the patients who, according to the documentation, did not know about their hyperuricemia.