Surveillance bias in the assessment of the size of COVID-19 epidemic waves: a case study.

OBJECTIVES: To estimate the size of COVID-19 waves using four indicators across three pandemic periods and assess potential surveillance bias. STUDY DESIGN: Case study using data from one region of Switzerland. METHODS: We compared cases, hospitalizations, deaths, and seroprevalence during three periods including the first three pandemic waves (period 1: Feb-Oct 2020; period 2: Oct 2020-Feb 2021; period 3: Feb-Aug 2021). Data were retrieved from the Federal Office of Public Health or estimated from population-based studies. To assess potential surveillance bias, indicators were compared to a reference indicator, i.e. seroprevalence during periods 1 and 2 and hospitalizations during the period 3. Timeliness of indicators (the duration from data generation to the availability of the information to decision-makers) was also evaluated. RESULTS: Using seroprevalence (our reference indicator for period 1 and 2), the 2nd wave size was slightly larger (by a ratio of 1.4) than the 1st wave. Compared to seroprevalence, cases largely overestimated the 2nd wave size (2nd vs 1st wave ratio: 6.5), while hospitalizations (ratio: 2.2) and deaths (ratio: 2.9) were more suitable to compare the size of these waves. Using hospitalizations as a reference, the 3rd wave size was slightly smaller (by a ratio of 0.7) than the 2nd wave. Cases or deaths slightly underestimated the 3rd wave size (3rd vs 2nd wave ratio for cases: 0.5; for deaths: 0.4). The seroprevalence was not useful to compare the size of these waves due to high vaccination rates. Across all waves, timeliness for cases and hospitalizations was better than for deaths or seroprevalence. CONCLUSIONS: The usefulness of indicators for assessing the size of pandemic waves depends on the type of indicator and the period of the pandemic.

Trends and regional variation in vertebroplasty and kyphoplasty in Switzerland: a population-based small area analysis.

Regional variation in procedure use often reflects the uncertainty about the risks and benefit of procedures. In Switzerland, regional variation in vertebroplasty and balloon kyphoplasty rates was high, although the variation declined between 2013 and 2018. Substantial parts of the variation remained unexplained, and likely signal unequal access and differing physician opinion. PURPOSE: To assess trends and regional variation in percutaneous vertebroplasty (VP) and balloon kyphoplasty (BKP) use across Switzerland. METHODS: We conducted a population-based analysis using patient discharge data from all Swiss acute care hospitals for 2013-2018. We calculated age/sex-standardized mean procedure rates and measures of variation across VP/BKP-specific hospital areas (HSAs). We assessed the influence of potential determinants of variation using multilevel regression models with incremental adjustment for demographics, cultural/socioeconomic, health, and supply factors. RESULTS: We analyzed 7855 discharges with VP/BKP from 31 HSAs. The mean age/sex-standardized procedure rate increased from 16 to 20/100,000 persons from 2013 to 2018. While the variation in procedure rates across HSAs declined, the overall variation remained high (systematic component of variation from 56.8 to 6.9 from 2013 to 2018). Determinants explained 52% of the variation. CONCLUSIONS: VP/BKP procedure rates increased and regional variation across Switzerland declined but remained at a high level. A substantial part of the regional variation remained unexplained by potential determinants of variation.

Physical activity is inversely associated with high blood pressure independently of overweight in Brazilian adolescents.

The purpose of this study was to assess the relationship between blood pressure (BP) levels and physical activity (PA) domains accounting for overweight/obesity. Adolescents aged 10 to 17 years old were recruited (n = 1021). International Obesity Task Force (IOTF) criteria were used to define overweight and obesity. High BP was defined using the Center of Disease Control and Prevention criteria. Different domains of PA (school activities, sport out of school, and leisure time PA) were assessed using a validated questionnaire. The prevalence of overweight/obesity was 21.9% for boys and 14.8% for girls. Some 13.4% of boys and 10.2% of girls, respectively, had high blood pressure (HBP). A strong and positive association was found between overweight and HBP. After adjustment for body mass index (BMI), total PA was inversely associated with BP. When all PA domains were entered simultaneously in a regression model, and after adjustment for BMI, only sport out of school was significantly and inversely associated with systolic BP [ß: -0.82 (-1.50; -0.13)]. These findings open avenue for the early prevention of HBP by the prevention of obesity and promotion of PA.

[Team-based care involving pharmacists and nurses to improve the management of hypertension]. / Améliorer la prise en charge de l'hypertension arterielle en favorisant la collaboration avec les pharmaciens et les infirmières.

Only half of hypertensive patients has controlled blood pressure. Chronic kidney disease (CKD) is also associated with low blood pressure control, 25-30% of CKD patients achieving adequate blood pressure. The Community Preventive Services Task Force has recently recommended team-based care to improve blood pressure control. Team-based care of hypertension involves facilitating coordination of care among physician, pharmacist and nurse and requires sharing clinical data, laboratory results, and medications, e.g., electronically or by fax. Based on recent studies, development and evaluation of team-based care of hypertensive patients should be done in the Swiss healthcare system.

Prevalence of overweight in the Seychelles: 15 year trends and association with socio-economic status.

We assessed the 15-year trends in the distribution of body mass index (BMI) and the prevalence of overweight in the Seychelles (Indian Ocean, African Region) and the relationship with socio-economic status (SES). Three population-based examination surveys were conducted in 1989, 1994 and 2004. Occupation was categorized as 'labourer', 'intermediate' or 'professional'. Education was also assessed in 1994 and 2004. Between 1989 and 2004, mean BMI increased markedly in all sex and age categories (overall: 0.16 kg m(-2) per calendar year, which corresponds to 0.46 kg per calendar year). The prevalence of overweight (including obesity, BMI >or= 25 kg m(-2)) increased from 29% to 52% in men and from 50% to 67% in women. The prevalence of obesity (BMI >or= 30 kg m(-2)) increased from 4% to 15% in men and from 23% to 34% in women. Overweight was associated inversely with occupation in women and directly in men in all surveys. In multivariate analysis, overweight was associated similarly (direction and magnitude) to occupation and education. In conclusion, the increasing prevalence of overweight and obesity over time in all age, sex and SES categories suggests large-scale changes in societal obesogenic factors. The sex-specific association of SES with overweight suggests that prevention measures should be tailored accordingly.

[Childhood obesity: definition, consequences, and prevalence]. / L'obésité chez les enfants: définition, conséquences et prevalence.

Since the 1980s, an epidemic of obesity is occurring worldwide among adults and children. The body mass index (BMI) is useful to determine whether a child is overweight or obese because BMI relates strongly to body fat mass. However, contrary to adults, BMI changes with sex and age in children. Sex- and age-specific norms for BMI of the International obesity task force (IOTF) are now widely used. Approximately 15-20% of schoolchildren in Switzerland are currently overweight (or obese) and 2-5% are obese. Obesity is a major public health challenge. It is associated with numerous short and long term health hazards (in particular cardiovascular and metabolic disorders, e.g. diabetes) and it tracks form childhood throughout adulthood. This emphasizes the need for programs and polices aimed at preventing paediatric obesity.

Prevalence of elevated blood pressure and association with overweight in children of a rapidly developing country.

We assessed the prevalence of elevated blood pressure (BP) and the association with excess body weight among a large sample of children in the Seychelles, a middle-income rapidly developing country in the African region. Weight, height and BP were measured in all children of four school grades in the Seychelles (Indian Ocean). Excess weight categories ('overweight' and 'obesity') were defined according to the criteria of the International Obesity Task Force. Two BP readings were obtained on one occasion. 'Elevated BP' was defined based on US reference tables. Data were available in 15,612 (86%) of 18,119 eligible children aged 5-16 years in 2002-2004. In all, 13.0% of Boys and 18.8% of girls were overweight or obese. The prevalence of elevated BP was 9.1% in boys and 10.1% in girls. Both systolic and diastolic BP were strongly associated with body mass index (BMI) in boys and in girls. In children with 'normal weight', 'overweight (and not obesity)' and 'obesity', respectively, proportions with elevated BP were 7.5, 16.9 and 25.2% in boys, and 7.5, 16.1 and 33.2% in girls. Overweight (including obesity) could account for 18% of cases of elevated BP in boys and 26% in girls. Further studies should examine the impact of the relationship between BMI and elevated BP on the burden of hypertension in the context of the epidemic of paediatric obesity.

[Influence of moderate body weight excess on the nycthemeral pattern of blood pressure, renal function and sodium and water excretion in patients with essential hypertension]. / Effet d'un excès de poids sur les variations nycthémérales de la pression artérielle, de la fonction rénale et de l'excrétion sodée chez des patients hypertendus.

Obesity is a risk factor for arterial hypertension. We studied the relationships between the body mass index (BMI) and the nycthemeral pattern of blood pressure (BP), renal function and sodium and water excretion (EX) in a group of 25 moderately hypertensive untreated men (41 +/- 2 y, 80 +/- 3 kg). Subjects were given a high sodium diet (6 g NaCl added to their usual diet, daily EX=200 mmol). On the 7th day, BP was monitored during 24 h and urine collected in 2 fractions (day=D, 8:00-22:00 and night=N, 22:00-8:00). Subjects were a posteriori divided into 2 groups according to the median BMI (26 kg/m2): Group 1, n=12, BMI 23.2 +/- 0.6 (mean +/- SEM) and Group 2, n=13, BMI 29.2 +/- 0.5 kg/m2. No difference was observed between the two groups for age, 24 h urine and sodium EX, or systolic and diastolic BP. However, heart rate was significantly higher during N in Group 2 (66 +/- 2 vs 57 +/- 2 b/min, p=0.012). Na and water EX were significantly higher during D than during N in Group 1, but lower during D than during N in Group 2. Creatinine clearance was higher in Group 2 than in Group 1 especially during N (D+29%, p=0.013; N+49%, p<0.001). In Group 2, subjects concentrated their urine more than in Group 1, as evaluated from the urine/plasma creatinine ratio (+49%, p=0.019). This ratio was positively correlated to BMI during D (r=0.561, p=0.004) but not during N. These results show that the glomerular hyperfiltration associated with overweight is more intense at night and that moderately overweight hypertensives have a reduced sodium and water EX during the day and a compensatory larger EX at night. The reduced diurnal EX goes along with an increased urine concentration. The nocturnal rise in EX is concomittant with a rise in heart rate. Given the growing health problems linked to obesity and hypertension, these results open a new field for the understanding of the difficulty to excrete sodium in this condition.

Comparative effects of losartan and irbesartan on serum uric acid in hypertensive patients with hyperuricaemia and gout.

OBJECTIVE: Losartan has been shown to increase urinary uric acid excretion and hence to lower serum uric acid levels. The purposes of the present study were: (1) to evaluate the effects of losartan on serum uric acid in hypertensive patients with hyperuricemia and gout, (2) to compare the effects of losartan with those of irbesartan, another angiotensin II receptor antagonist and (3) to evaluate whether losartan 50 mg b.i.d. has a greater impact on serum uric acid levels than losartan 50 mg once a day. METHODS: Thirteen hypertensive patients with hyperuricaemia and gout completed this prospective, randomized, double-blind, cross-over study. Uric acid-lowering drugs were stopped 3 weeks before the beginning of the study. Patients were randomized to receive either losartan 50 mg or irbesartan 150 mg once a day, for 4 weeks. During this phase, a placebo was given in the evening. After 4 weeks, the dose was increased to losartan 50 mg b.i.d., or irbesartan 150 mg b.i.d. for another 4 week period. Subsequently, the patients were switched to the alternative treatment modality. Enalapril (20 mg o.d.) was given during the run-in period and between the two treatment phases. Serum and urinary uric acid were measured at the beginning and at the end of each treatment phase. RESULTS: Our results show that losartan 50 mg once daily decreased serum uric acid levels from 538 +/- 26 to 491 +/- 20 micromol/l (P < 0.01). Irbesartan had no effect on serum uric acid. Increasing the dose of losartan from 50 mg o.d. to 50 mg twice a day, did not further decrease serum uric acid. This may in part be due to a low compliance to the evening dose as measured with an electronic device. Indeed, whatever the prescribed drug, the mean compliance of the evening dose was always significantly lower than that of the morning dose. The uricosuric effect of losartan appears to decrease with time when a new steady state of lower serum uric acid is reached. CONCLUSIONS: In contrast to irbesartan, losartan was uricosuric and decreased serum uric acid levels. Losartan 50 mg b.i.d. did not produce a greater fall in serum uric acid than losartan once a day. Losartan might be a useful therapeutic tool to control blood pressure and reduce serum uric acid levels in hypertensive patients with hyperuricaemia and gout.

Renal and neurohormonal responses to increasing levels of lower body negative pressure in men.

BACKGROUND: The stimulation of efferent renal sympathetic nerve activity induces sequential changes in renin secretion, sodium excretion, and renal hemodynamics that are proportional to the magnitude of the stimulation of sympathetic nerves. This study in men investigated the sequence of the changes in proximal and distal renal sodium handling, renal and systemic hemodynamics, as well as the hormonal profile occurring during a sustained activation of the sympathetic nervous system induced by various levels of lower body negative pressure (LBNP). METHODS: Ten healthy subjects were submitted to three levels of LBNP ranging between 0 and -22.5 mm Hg for one hour according to a triple crossover design, with a minimum of five days between each level of LBNP. Systemic and renal hemodynamics, renal water and sodium handling (using the endogenous lithium clearance technique), and the neurohormonal profile were measured before, during, and after LBNP. RESULTS: LBNP (0 to -22.5 mm Hg) induced an important hormonal response characterized by a significant stimulation of the sympathetic nervous system and gradual activations of the vasopressin and the renin-angiotensin systems. LBNP also gradually reduced water excretion and increased urinary osmolality. A significant decrease in sodium excretion was apparent only at -22.5 mm Hg. It was independent of any change in the glomerular filtration rate and was mediated essentially by an increased sodium reabsorption in the proximal tubule (a significant decrease in lithium clearance, P < 0.05). No significant change in renal hemodynamics was found at the tested levels of LBNP. As observed experimentally, there appeared to be a clear sequence of responses to LBNP, the neurohormonal response occurring before the changes in water and sodium excretion, these latter preceding any change in renal hemodynamics. CONCLUSIONS: These data show that the renal sodium retention developing during LBNP, and thus sympathetic nervous stimulation, is due mainly to an increase in sodium reabsorption by the proximal segments of the nephron. Our results in humans also confirm that, depending on its magnitude, LBNP leads to a step-by-step activation of neurohormonal, renal tubular, and renal hemodynamic responses.

Electronic compliance monitoring in resistant hypertension: the basis for rational therapeutic decisions.

OBJECTIVE: Incomplete compliance is one of several possible causes of uncontrolled hypertension. Yet, non-compliance remains largely unrecognized and is falsely interpreted as treatment resistance, because it is difficult to confirm or exclude objectively. The goal of this study was to evaluate the potential benefits of electronic monitoring of drug compliance in the management of patients with resistant hypertension. METHODS: Forty-one hypertensive patients resistant to a three-drug regimen (average blood pressure 156/ 106 +/- 23/11 mmHg, mean +/- SD) were studied prospectively. They were informed that for the next 2 months, their presently prescribed drugs would be provided in electronic monitors, without any change in treatment, so as to provide the treating physician with a measure of their compliance. Thereafter, patients were offered the possibility of prolonging the monitoring of compliance for another 2 month period, during which treatment was adapted if necessary. RESULTS: Monitoring of compliance alone was associated with a significant improvement of blood pressure at 2 months (145/97 +/- 20/15 mmHg, P < 0.01). During monitoring, blood pressure was normalized (systolic < 140 mmHg or diastolic < 90 mmHg) in one-third of the patients and insufficient compliance was unmasked in another 20%. When analysed according to tertiles of compliance, patients with the lowest compliance exhibited significantly higher achieved diastolic blood pressures (P = 0.04). In 30 patients, compliance was monitored up to 4 months and drug therapy was adapted whenever necessary. In these patients, a further significant decrease in blood pressure was obtained (from 150/100 +/- 18/15 to 143/94 +/- 22/11 mmHg, P = 0.04/0.02). CONCLUSIONS: These results suggest that objective monitoring of compliance using electronic devices may be a useful step in the management of patients with refractory hypertension, as it enables physicians to take rational decisions based on reliable and objective data of drug compliance and hence to improve blood pressure control.

Renal sodium handling in acute and chronic salt loading/depletion protocols: the confounding influence of acute water loading.

OBJECTIVES: Renal tubular sodium handling was measured in healthy subjects submitted to acute and chronic salt-repletion/salt-depletion protocols. The goal was to compare the changes in proximal and distal sodium handling induced by the two procedures using the lithium clearance technique. METHODS: In nine subjects, acute salt loading was obtained with a 2 h infusion of isotonic saline, and salt depletion was induced with a low-salt diet and furosemide. In the chronic protocol, 15 subjects randomly received a low-, a regular- and a high-sodium diet for 1 week. In both protocols, renal and systemic haemodynamics and urinary electrolyte excretion were measured after an acute water load. In the chronic study, sodium handling was also determined, based on 12 h day- and night-time urine collections. RESULTS: The acute and chronic protocols induced comparable changes in sodium excretion, renal haemodynamics and hormonal responses. Yet, the relative contribution of the proximal and distal nephrons to sodium excretion in response to salt loading and depletion differed in the two protocols. Acutely, subjects appeared to regulate sodium balance mainly by the distal nephron, with little contribution of the proximal tubule. In contrast, in the chronic protocol, changes in sodium reabsorption could be measured both in the proximal and distal nephrons. Acute water loading was an important confounding factor which increased sodium excretion by reducing proximal sodium reabsorption. This interference of water was particularly marked in salt-depleted subjects. CONCLUSION: Acute and chronic salt loading/salt depletion protocols investigate different renal mechanisms of control of sodium balance. The endogenous lithium clearance technique is a reliable method to assess proximal sodium reabsorption in humans. However, to investigate sodium handling in diseases such as hypertension, lithium should be measured preferably on 24 h or overnight urine collections to avoid the confounding influence of water.

[Accidental morbidity in adolescence: a retrospective study in 12 to 15 year-old school children in Switzerland] . / Morbidité accidentelle à l'adolescence: une étude représentative auprès des écoliers de 12 à 15 ans en Suisse.

Mortality and morbidity from injuries in the adolescent population is substantial in Switzerland as all over the world. The estimation of morbidity from injuries is difficult and depends on the design of the study. Little information is available on morbidity between ages 12 and 15. The Health Behaviour in School-Aged Children (HBSC) study is an international survey based on a self-administered questionnaire for which the Swiss Institute for Prevention of Alcohol and Drug Problems (SIPA) is responsible in Switzerland. 7196 schoolchildren aged 12 to 15 participated in the 1998 survey. Questions covered subjects such as health and health behaviour. A few questions covered injuries, with reference to frequency, context and consequences. 45.3% of adolescents have been treated at least once by a nurse or a doctor for an injury during the past 12 months. It can be deduced that nearly 149,000 adolescents aged between 12 and 15 are injured in more than 260,000 accidents in Switzerland. The rate of injury is 793 per 1000 adolescents per year. Furthermore, one adolescent out of ten injures himself three times or more per year. In conclusion, morbidity due to injuries in adolescents aged 12 to 15 in Switzerland is therefore considerable. This study demonstrates the high prevalence of repeated injuries in adolescents.