Kenji Ohshige

Influence of socioeconomic factors on medically unnecessary ambulance calls

BackgroundUnnecessary ambulance use has become a socioeconomic problem in Japan. We investigated the possible relations between socioeconomic factors and medically unnecessary ambulance calls, and we estimated the incremental demand for unnecessary ambulance use produced by socioeconomic factors.MethodsWe conducted a self-administered questionnaire-based survey targeting residents of Yokohama, Japan. The questionnaire included questions pertaining to socioeconomic characteristics, dichotomous choice method questions pertaining to ambulance calls in hypothetical nonemergency situations, and questions on the citys emergency medical system. The probit model was used to analyze the data.ResultsA total of 2,029 out of 3,363 targeted recipients completed the questionnaire (response rate, 60.3%). Probit regression analyses showed that several demographic and socioeconomic factors influence the decision to call an ambulance. Male respondents were more apt than female respondents to state that they would call an ambulance in nonemergency situations (p < 0.05). Age was an important factor influencing the hypothetical decision to call an ambulance (p < 0.05); elderly persons were more apt than younger persons to state that they would call an ambulance. Possession of a car and hesitation to use an ambulance negatively influenced the hypothetical decision to call an ambulance (p < 0.05). Persons who do not have a car were more likely than those with a car to state that they would call an ambulance in unnecessary situations.ConclusionResults of the study suggest that several socioeconomic factors, i.e., age, gender, household income, and possession of a car, influence a persons decision to call an ambulance in nonemergency situations. Hesitation to use an ambulance and knowledge of the citys primary emergency medical center are likely to be important factors limiting ambulance overuse. It was estimated that unnecessary ambulance use is increased approximately 10% to 20% by socioeconomic factors.

Seasonal influence on blood pressure in elderly normotensive subjects.

The aim of this study was to examine whether or not fluctuations in blood pressure (BP) differ by season. Subjects were 45 elderly individuals (20 men and 25 women; mean age, 66.5±4.9 [SD] years). Each subjects BP was recorded with an ambulatory BP monitoring device for 24 h during each of the four seasons. Subjects also wore a portable weather meter to obtain ambient temperature, relative humidity, and barometric pressure simultaneously with BP. The relationships between meteorologic values and BP were investigated at various parts of the day. Seasonal differences in BP fluctuation around wake-up-time were analyzed by means of the Tukeys test. The difference between the pre–wake-up-time systolic BP and the wake-up-time systolic BP was significantly greater in winter than in summer (8.7 mmHg greater, p<0.001). The difference between pre–wake-up-time and wake-up-time systolic BP was significantly greater in autumn than in spring (9.4 mmHg greater, p<0.001) or summer (13.1 mmHg greater, p<0.001). The difference between pre–wake-up-time heart rate and wake-up-time heart rate did not differ statistically between seasons. In conclusion, the present study showed that the difference between pre–wake-up-time systolic BP and wake-up-time systolic BP was greatest in the colder seasons, i.e., autumn and winter. There appears to be a large fluctuation in wake-up-time in the colder seasons. Low ambient temperature likely induces this large fluctuation.

Clinical features of Vibrio vulnificus infections in the coastal areas of the Ariake Sea, Japan

Vibrio vulnificus infection can result in necrotizing fasciitis and sepsis and is associated with high mortality. Most patients infected with this microbe have liver dysfunction as an underlying disease. However, because of the sporadic nature of outbreaks and unidentified cases, extensive evaluation of clinical features and identification of factors affecting prognosis have not been performed. We retrospectively analyzed 37 cases in Japan from 1984 to 2008 to review clinical features and to identify risk factors associated with prognosis. Statistical differences between clinical features (patient’s characteristics, initial clinical laboratory data, symptoms upon admission, and other risk indicators) and prognosis were analyzed by use of the χ2 test or the Mann–Whitney U test. Multivariate logistic regression analysis was also performed to assess factors which potentially affect hospital mortality. The mortality rate was 64.9%. An underlying liver disease was observed in 91.6% of the patients. The presence of liver cirrhosis tended to be related to hospital mortality; however, statistical significance was not achieved. Advanced age, lower platelet counts, and the presence of extensive skin lesions at onset affected outcomes with statistical significance. The prognosis of this disease is poor, because septic shock and necrotizing fasciitis often develop within a few days. Early diagnosis and treatment are needed to improve the prognosis of V. vulnificus infection.

Reduction in Ambulance Transports during a Public Awareness Campaign for Appropriate Ambulance Use

OBJECTIVES This study aimed to characterize the change in the upward trend in monthly ambulance transports that occurred during a citywide campaign for appropriate ambulance use. This study also investigated whether the number of ambulance transports for individuals with nonserious conditions decreased separately from the decrease in ambulance transports for individuals with serious conditions. METHODS A retrospective time series survey was carried out on the number of ambulance transports that occurred per month over a 10-year period (1997-2006). This study focused on individuals transported by ambulance because of illness. Seasonal decomposition was applied to adjust for the seasonal effect on ambulance transport. The shift in the trend during the campaign period (April 2005-December 2006) was examined by means of linear regression analysis. RESULTS The number of individuals transported by ambulance decreased during the campaign period. A decrease in the number of ambulance transports was observed for both nonserious and serious conditions. During the campaign period, the number of ambulance transports per month was estimated to have decreased by 530 (approximately 7%; 95% confidence interval [CI] = -729 to -331) for individuals with nonserious conditions and by 37 (approximately 8%; 95% CI = -53 to -22) for individuals with serious conditions. CONCLUSIONS A campaign to educate the public on appropriate ambulance use may reduce ambulance calls for both nonserious and serious conditions.

Cross-sectional study on risk factors of HIV among female commercial sex workers in Cambodia

To describe epidemiological features on HIV prevalence among female commercial sex workers (CSWs), a cross-sectional study on sexual behaviour and serological prevalence was carried out in Cambodia. The CSWs were interviewed on their demographic characters and behaviour and their blood samples were taken for testing on sexually transmitted diseases, including HIV, Chlamydia trachomatis, syphilis, and hepatitis B. Associations between risk factors and HIV seropositivity were analysed. High seroprevalence of HIV and Chlamydia trachomatis IgG antibody (CT-IgG-Ab) was shown among the CSWs (54 and 81.7%, respectively). Univariate logistic regression analyses showed an association between HIV seropositivity and age, duration of prostitution, the number of clients per day and CT-IgG-Ab. Especially, high-titre chlamydial seropositivity showed a strong significant association with HIV prevalence. In multiple logistic regression analyses, CT-IgG-Ab with higher titre was significantly independently related to HIV infection. These suggest that existence of Chlamydia trachomatis is highly related to HIV prevalence.

Influence of Mental Stress on Cardiovascular Function as Evaluated by Changes in Energy Expenditure

We assessed the influence of mental stress on cardiovascular parameters, including systolic blood pressure (SBP), heart rate (HR) and sympathetic activity (LF/HF), with the use of a quantitative indicator of energy expenditure (EE). Forty-four male university students underwent a mental arithmetic test. Their EE was 1.3-fold that at rest in response to the test. Change in EE (ΔEE) in response to the test was compared between subjects with high blood pressure (BP) and those without and between subjects with high salt intake and those without. Changes in SBP (ΔSBP), changes in HR (ΔHR) and changes in LF/HF (ΔLF/HF) in relation to ΔEE were represented by linear regression. Regression analysis showed that the coefficients of ΔEE were positively related to the dependent variables ΔSBP, ΔHR and ΔLF/HF. The slopes of the regression curves for the high-BP group (24-h SBP ≥127 mmHg) and the high-salt–intake group (≥11 g/day) were steeper than those for the normal BP group and the low-salt–intake group (p=0.11 and p=0.01, respectively). Thus, we were able to determine the influence of mental stress on cardiovascular function. The influence of mental stress on cardiovascular function likely differs according to a subjects environmental conditions. Our study implied that high salt intake increases the sensitivity of cardiovascular functions to mental stress.

Neither the presence of metabolic syndrome as defined by the IDF guideline nor an increased waist circumference increased the risk of microvascular or macrovascular complications in Japanese patients with type 2 diabetes

The aim of this study was to evaluate the relationship between the diagnosis of metabolic syndrome (MetS) or its components and the prevalence of microvascular and macrovascular complications in 130 Japanese type 2 diabetic patients. Out of the 130 patients, 58.5% satisfied the criteria of the MetS as defined by the IDF guideline. The results of logistic regression analysis with adjustment for three variables (age, gender and duration of diabetes) revealed that the presence of MetS as defined by the IDF guideline was not independently related to the presence of proliferative retinopathy, proteinuria, neuropathy, or macrovascular disease in the diabetic patients. The waist circumference per se was not associated with diabetic neuropathy, retinopathy, nephropathy, or macrovascular diseases. These results suggest that neither the presence of MetS, as defined by the IDF guideline, nor the waist circumference was associated with the presence of either microvascular or macrovascular complications in Japanese type 2 diabetic patients.

Masked Hypertension in Elderly Managerial Employees and Retirees

Masked hypertension is reported to have the same level of hazard risk of cardiovascular mortality and stroke morbidity as sustained hypertension. The number of managerial employees suffering from cardiovascular disease and stroke is known to be greater than other employee. The aim of this study was to compare the 24-h blood pressure (BP) recordings between elderly male managerial employees and retirees and to propose a strategy for identifying masked hypertension. A total of 38 males (16 managerial employees aged 50–69 years and 22 retirees aged 60–65 years) who were not taking any antihypertensive medications participated in this study. Their 24-h BP was measured by an ambulatory BP monitoring device. Daytime (9:00–17:00 h) BPs of the employees (mean, 139/92 mm Hg) were significantly higher than in the retirees (mean 124/80 mm Hg), while there was no difference in BP before and during sleep. In all, 5 of 16 employees (31%) who were diagnosed as normotensive (<140/90 mm Hg) at a periodic health check had hypertension (>135/85 mm Hg) in the morning measured by ambulatory BP monitoring, while 6 (38%) had a similar level of hypertension during the daytime (9:00–17:00h). These individuals were diagnosed as having masked hypertension. Multiple regression analyses showed that the job was the only factor that contributed to the difference in BP in the subjects during the daytime. This finding suggested that job stress seemed to be one of the main causes of masked hypertension. We argue that more frequent measurements of BP at the work place are necessary to identify subjects with masked hypertension.

Relation between Nocturnal Arterial Oxygen Desaturation and Morning Blood Pressure

Objective. Arterial oxygen saturation (SpO2) in volunteers had been previously investigated, and the possibility that a decrease in SpO2 leads to an increase in blood pressure (BP) in airline passengers experiencing oxygen desaturation at high altitudes was reported. It was also shown that mean nocturnal SpO2 was lower in subjects with high-normal BP or mild hypertension than in those with normal BP. The present study investigated nocturnal SpO2, evening BP, and morning BP of volunteers during daily life and examined the relation between nocturnal SpO2 and change in BP (morning BP minus evening BP) to determine the influence of SpO2 on BP. Methods. Sixty-two volunteers (31 men and 31 women) aged 40–87 years (mean: 55.9 ± 12 [SD] years) underwent measurement of SpO2 and heart rate with a ring-shaped pulse oximeter during sleep at home. Evening BP and morning BP were measured by automatic BP recorder. Subjects that were classified as having high SpO2 (mean nocturnal SpO2 ≥ 95%; n = 23, 10 men and 13 women; mean age: 53.2 ± 12 years) or low SpO2 (mean nocturnal SpO2 < 94%; n = 21, 12 men and 9 women; mean age: 58.7 ± 13 years) were compared. The relation between mean nocturnal SpO2 and morning BP and the relation between mean nocturnal SpO2 and change in BP were investigated. Results. There was a significant negative correlation between mean nocturnal SpO2 and morning systolic BP (SBP; r = −0.50, p < 0.01) and between mean nocturnal SpO2 and morning diastolic BP (DBP; r = −0.37, p < 0.01). A significant negative correlation between mean nocturnal SpO2 and change in SBP was observed (r = −0.57, p < 0.01). Morning BP was significantly higher in the low nocturnal SpO2 group than in the high nocturnal SpO2 group (p < 0.001). Conclusion. The increase in morning BP from evening BP was significantly greater in subjects with a low nocturnal SpO2. The decrease in SpO2 during sleep may affect morning BP rise.

High serum alanine aminotransferase levels for the first three successive years can predict very high incidence of hepatocellular carcinoma in patients with Child Stage A HCV-associated liver cirrhosis.

Abstract Objective. To assess retrospectively whether continuously high serum alanine aminotransferase (ALAT) levels (<80 IU) in the first three successive years after the diagnosis of liver cirrhosis (LC) are predictive of a subsequent high incidence of hepatocellular carcinoma (HCC) in patients with Child Stage A hepatitis C virus (HCV)-LC. Material and methods. The study comprised 132 HCV-LC (Child Stage A) patients who had not received interferon therapy but had been treated with anti-inflammatory agents. At the end of a 3-year follow-up after the diagnosis of LC, the patients were subdivided into three groups according to their serum ALAT levels and the subsequent incidence of HCC was assessed. Results. The cumulative incidence of HCC starting from 3 years after the diagnosis of LC in the continuously high ALAT group (annual average over 3 years always ≥80 IU; n=41; Group A) was markedly higher than that in the continuously low ALAT group (always <80 IU; n=48; Group B) (p<0.005) during an observation period of 7.9±3.7 years. The incidence of HCC in Group A was 11.8%/year. The odds ratios of developing HCC in Group A and Group C (mixed high and low ALAT levels; n=43) were 5.1-fold and 1.5-fold that of Group B, respectively. A multivariate analysis revealed that the ALAT group was independently associated with HCC development. Conclusions. Continuously high ALAT levels for three successive years following the diagnosis of LC can be predictive of a very high incidence of HCC in Child A HCV-LC patients. Prospective trials using therapeutic approaches aimed at decreasing ALAT levels are necessary in order to confirm a positive impact of ALAT reduction on the incidence of HCC in patients with HCV-LC.