The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

BACKGROUND

The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications.

METHODS

ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery.

RESULTS

The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784.

CONCLUSIONS

This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance.

CLINICAL TRIAL REGISTRATION

NCT03044899.

Health-related quality of life during the first year after a hip fracture: results of the Mexican arm of the International Cost and Utility Related to Osteoporotic Fractures Study (MexICUROS)

We investigated changes in health-related quality of life (HRQoL) due to hip fracture in Mexican adults aged ≥ 50 years during the first year post-fracture. Mean accumulated loss was 0.27 quality-adjusted life years (QALYs). HRQoL before fracture was the main contributor to explain the loss of QALYs.

INTRODUCTION

We aimed to estimate the health-related quality of life (HRQoL) loss over 1 year in patients sustaining a hip fracture in Mexico.

METHODS

Individuals aged ≥ 50 years old with diagnosis of a low-energy-induced hip fracture enrolled in the International Costs and Utilities Related to Osteoporotic Fractures Study (ICUROS) composed the study population. After a recall of their own pre-fracture status, HRQoL was prospectively collected in three phases over 12 months of follow-up using EQ-5D-3L. The UK preference weight set was applied to calculate the utility values. The accumulated quality-adjusted life years (QALYs) loss in the first year post-fracture was estimated using the trapezoid method. Multivariate regression analysis allowed identifying determinants of QALYs loss.

RESULTS

One hundred ninety-three patients (mean ± SD age 77.2 ± 9.9 years; 80% women; 15.5% with prior fracture in the last 5 years; 78% in low-income category) were evaluated. Mean (95% CI) utility value before fracture was 0.64 (0.59-0.68). It dropped to 0.01 (0.01-0.02) immediately after fracture and then improved to 0.46 (0.42-0.51) and 0.60 (0.55-0.64) at 4 and 12 months post-fracture, respectively. Disregarding fracture-related mortality, accumulated QALYs loss over the first year was 0.27 (0.24-0.30) QALYs. Mobility, self-care, and usual activities were the most affected domains throughout the whole year. HRQoL before fracture was the main contributor to explain the loss of QALYs.

CONCLUSIONS

Hip fractures reduce dramatically the HRQoL, with the loss sustained at least over the first year post-fracture in Mexico. The utility values derived from this study can be used in future economic evaluations.

Increasing age- and sex-specific rates of hip fracture in Mexico: a survey of the Mexican Institute of Social Security

This study, characterising the incidence of hip fracture in Mexico, showed that age- and sex-specific rates increased between 2000 and 2006. The demographic changes estimated for Mexico indicate that the annual number of hip fractures will rise from 29,732 in 2005 to 155,874 in 2050. If the age-specific incidence of hip fracture continues, the number of hip fractures would increase by a further 46%.

INTRODUCTION

The aim of the present study was to determine time trends, if any, in hip fracture rates for Mexico and to forecast the number of hip fractures expected in Mexico over the coming years up to 2050.

METHODS

All hip fracture cases registered during the years 2000-2006 were collected at all the second and tertiary-care hospitals across the country from one of the largest health systems in Mexico, The Instituto Mexicano del Seguro Social (IMSS).

RESULTS

Between the years 2000 and 2006, the age-specific incidence of hip fracture increased significantly both for men and women by 1% per year (p = 0.016 and p < 0.001, respectively). In 2005, there were there were 29,732 hip fractures estimated in Mexico, 68% of which were found in women. Assuming no change in the age- and sex-specific incidence of hip fracture, the number of hip fractures was expected to increase markedly with time to 155,874 in 2050. Assuming that the age-specific incidence continues, the number of hip fractures in men and women would increase by a further 46% to 226,886 in 2050.

CONCLUSION

Demographic changes estimated for Mexico indicate that the annual number of hip fractures will rise from 29,732 in 2005 to 155,874 expected in 2050. If the age-specific incidence of hip fracture continues to rise, the number of hip fractures would increase by a further 46%.

Direct costs of osteoporosis and hip fracture: an analysis for the Mexican healthcare system

This study reports the direct costs related to osteoporosis and hip fractures paid for governmental and private institutions in the Mexican health system and estimates the impact of these entities on Mexico. We conclude that the economic burden due to the direct costs of hip fracture justifies wide-scale prevention programs for osteoporosis (OP).

METHODS

To estimate the total direct costs of OP and hip fractures in the Mexican Health care system, a sample of governmental and private institutions were studied. Information was gathered through direct questionnaires in 275 OP patients and 218 hip fracture cases. Additionally, a chart review was conducted and experts' opinions obtained to get accurate protocol scenarios for diagnoses and treatment of OP with no fracture. Microcosting and activity-based costing techniques were used to yield unit costs.

RESULTS

The total direct costs for OP and hip fracture were estimated for 2006 based on the projected annual incidence of hip fractures in Mexico. A total of 22,233 hip fracture cases were estimated for 2006 with a total cost to the healthcare system of US$ 97,058,159 for the acute treatment alone ($4,365.50 per case). We found considerable differences in costs and the way the patients were treated across the different health sectors within the country.

CONCLUSION

Costs of the acute treatment of hip fractures in Mexico are high and are expected to increase with the predicted increment of life expectancy and the number of elderly in our population.

Changes in the upper airway of patients who wear a modified functional appliance to treat obstructive sleep apnea

This study was designed to investigate changes that occur in the upper airway of patients with obstructive sleep apnea who use a modified functional appliance. The experimental group included 10 men, all diagnosed with obstructive sleep apnea. Nuclear magnetic resonance imaging was carried out on each patient. One image was taken when the patient was in maximum habitual occlusion and another was taken while the patient wore the appliance. From the images gained, a three-dimensional reconstruction of the upper airway from the palatal plane was achieved. The images revealed statistically significant increases in the volume of the upper airway with the use of a modified functional appliance. Three-dimensional studies of the upper airway show greater detail and therefore seem likely to have more validity than two-dimensional studies.