Those who received examination results via face-to-face counselling were the oldest and had the poorest cardiometabolic parameters (BMI, waist circumference, systolic blood pressure, HDL cholesterol) and glucose metabolic indices (fasting blood glucose, glycosylated haemoglobin) as compared to the groups that received mail or telephone counselling. However, in the face-to-face counselling group, total cholesterol and LDL cholesterol levels showed greater improvement after health examination, compared to the other two groups. This pattern of results was similar but non-significant for triglyceride levels.
Previous studies [4, 5] have shown that private check-up examinees have lower subjective and objective health statuses. Shin et al.  compared those who received both the National Health Insurance Service health check-ups and the private health check-ups with those who received only the private health check-ups. They reported that those who received both private and national check-ups were aware of their poor health status and had higher obesity levels. In addition, those who answered ‘normal’, ‘healthy’ or ‘very healthy’ for subjective health status were 66–71% less likely to receive private check-ups than those who answered ‘bad’. However, this study had limitations in that it had only 297 participants. Kang et al. , from the nationwide Korean Longitudinal Study of Ageing (KLoSA), demonstrated that patients who had private check-ups had lower subjective health statuses. The incidence of hypertension and cancer was also higher for these patients than for patients who did not receive private check-ups. Furthermore, Yeo  reported that the more chronic disease, the higher the probability of receiving private check-ups.
In this study, participants may have chosen face-to-face counselling instead of mail or telephone counselling because they required detailed explanation of their conditions. Their older age, less favourable check-ups results, and self-awareness regarding their health statuses may have led to them choosing face-to-face counselling. However, during the six years of study period, proportions of counselling methods remained unchanged: 79.1%, mail counselling; 10.5%, telephone counselling; and 10.5%, face-to-face counselling. This indicates that examinees seem to choose the same counselling method as before without concerned about the form of counselling they receive after an examination.
In patients with dyslipidaemia, lifestyle modifications such as proper diet, regular aerobic exercise, and weight control can reduce total cholesterol, LDL cholesterol, and triglyceride by 7–18%, and increase HDL cholesterol by 2–18% . However, lapses into bad habits may have to be overcome repeatedly, before positive lifestyle modifications become cemented . During this transitional phase, maintenance motives, self-regulation, resources, habits, and contextual influences are required for the instatement of lifestyle changes. Also, in a systematic review and meta-analysis of the motivational interview on behavioural change, Sune et al.  reported that the interview was effective only if conducted more than once and was always effective if conducted more than five times. In subsequent systematic reviews, Patnode et al.  demonstrated that changes to the number of counselling sessions effected proportional behavioural change. During the design of the current study, this shaped the decision to recruit only patients who received three or more sessions.
Despite relatively high overall satisfaction rates with private health examinations, little counselling and education seems to take place after these examinations. A previous study  on the satisfaction survey of the examinees showed that both national and private check-ups received the lowest score in ‘sufficiency of counselling and education after check-ups’, and the next lowest score in ‘relevant data after check-ups/excellent guidance for follow-up’. Moreover, the demand for counselling is increasing.
In a previous study , short motivational interviewing of only 15 minutes was shown to be effective in the treatment of lifestyle problems and disease. Therefore, patients who review the results of their examinations with their doctors and talk about a health promotion plan could develop improved lipid profiles relative to those who simply read letters containing their results and consultation information. Although a few reports [13, 14] have indicated that telemedicine is more cost-effective than face-to-face medical care, due to recent advances in information and communication technology (ICT), the results of the current study support the most basic principle —direct patient education is the most effective method of managing chronic diseases.
There are several limitations to our study. First, ours was a single-centre study and may not have contained a sample that was representative of the overall population. Second, since the participants’ previous histories were not included, those with normal lipid profiles and no treatment or counselling needed may have also been included in the study. In addition, this study did not consider that the goals and treatment methods associated with dyslipidaemia differ according to levels of cardiovascular risks. However, in a recent study  of young adults aged 20 to 39 years in Korea, the risks of ischaemic heart disease and cerebrovascular disease were reduced if total cholesterol levels were reduced to a lower class than was observed in the previous examination, when dividing total cholesterol levels into the following categories: low (< 180 mg/dL), middle (180–240 mg/dL), high (≥ 240 mg/dL). Therefore, it is meaningful to compare the degree of change in cholesterol levels alone, as was done in the current study. Third, because we did not include the drug history of the participants, changes in cholesterol levels may be attributable to drugs or other causes rather than the effects of lifestyle modifications. However, patients with dyslipidaemia have lower compliance rates with the drugs than do those with hypertension and diabetes [17–19]. And in previous studies , patients who received follow-up treatment within the first three months following medication had higher subsequent compliance rates, as compared to those who received no follow-up treatment. Therefore, regardless of drug effects, it is meaningful that compliance rates and the results of medical examination related to chronic diseases are improved due to increase in post-check-up behaviours, such as visiting the hospital and picking up medicine. Fourth, because the study included data from September 2013 to August 2019, it is impossible to know which forms of counselling were received before September 2013, and effects of these sessions cannot be overlooked. In order to correct for this problem, additional analyses of chi-square tests, one-way analyses of variance(ANOVA) and Scheffé post-hoc analyses were performed only for participants (n = 4,919) who conducted the first check-ups at our health check-up centre. However, the baseline characteristics of the participants were not significantly different from those of the participants in this study. In addition, even if the first examination was conducted at our health check-up centre, it may not be the first examination in one’s life, so the influence of a previous examination cannot be completely excluded, using any analysis method.