Most study patients were “highly compliant” with using this mobile technology, and it might help in clinical trials of potential treatments or with judging existing treatment effectiveness “in the real-world setting,” its researchers wrote. Six-month findings showed weight increased by 2.35% and BMI by 1.42% among PWS adolescents and adults.
The study, “Variability and change over time of weight and BMI among adolescents and adults with Prader-Willi syndrome: a 6-month textbased observational study,” was published in the Orphanet Journal of Rare Diseases.
PWS is caused by the loss of paternal genes in chromosome 15 that control metabolism, appetite, growth, intellectual abilities, and social behavior.
Infants with PWS show signs of fatigue, hypotonia (poorer muscle tone), and problems with movement and feeding. Severe changes in appetite arise after early childhood, when excessive appetite, or hyperphagia, begins. Adolescents and adults with PWS typically become morbidly obese without dietary restrictions.
Low physical activity, abnormal body composition, and slow metabolism rates further contribute to the propensity for obesity in PWS, and the risk of serious complications, including cardiovascular disease, and diabetes.
Recombinant (lab-made) human growth hormone (GH) is the only therapy for children with PWS currently approved in the U.S. It helps to normalize growth, improve body composition, and with patients’ cognition and behavior, but GH has no effect on hyperphagia.
Because early diagnosis and family education are crucial to good weight control, it is important to understand weight changes over time in patients at their home.
Researchers at the Foundation for Prader-Willi Research evaluated the feasibility of using a remote technology — text messages — to track such changes .
In total, 165 teenagers and adults, ages 12 to 48 (mean age, 19.7), were enrolled.
At the study’s start (baseline), the scientists collected data on their sex, age, growth hormone therapy, and height. Weight was collected once a week for six months (26 weeks), while data on BMI, a measure of body fat, and height were collected at baseline and at three and six months.
Questions regarding access to food, activity levels, and medication use, and “major life” changes in any of these areas, were also evaluated at these time points.
At baseline, patients’ average height was 157.2 cm (just over 5 feet; 163.2 cm for males and 151.3 cm for females). Mean weight was 76.8 kg (169 lbs), but weight was highly variable, ranging from 33.2 kg (73 lbs) to 207.7 kg (457 lbs). In turn, mean BMI was 31.4 kg per square meter (kg/m2), but ranged from 13.2 kg/m2 to 88 kg/m2.
Among the 161 patients with available data and according to BMI values, 0.6% of these people were underweight (one participant), 32.3% were normal weight (52 patients), 14.9% were overweight (24 participants) and 52.2% were obese (84 participants). These groupings did not change significantly during the six months of follow-up.
Almost 60% (98 participants) were using GH therapy.
Overall, weight increased over the study’s duration, with a mean increase of 1.8 kg, from 76.8 to 78.6 kg. Mean percent weight increased by 2.35%. “[A]dults in this PWS population show faster increases in weight compared to the adult United States average,” the researchers wrote.
In turn, average BMI remained relatively stable, but still high — 31.4 kg/m2 at baseline, 31.3 kg/m2 at three months, and 31.5 kg/m2 at six months. This corresponded to a mean BMI increase of 1.42% at six months.
Individual changes in both weight and BMI ranged from 20.8% decreases to 31.2% increases.
During the study, 33% of participants reported having a major life change: 30.1% in food access, 53.4% in activity levels, and 43.2% switched medication.
In a statistical analysis, the researchers found that time, sex, age, time on GH therapy, major life changes, and change in food access were the factors that most influenced variations in weight and BMI.
For every percent increase in time on GH therapy, BMI decreased by 0.41% and weight decreased by 0.22%, results showed. For every year increase in age, percent change in weight lowered by 0.2%.
Most study participants completed weight measures using text messaging, with 95.1% of weeks collecting data. Two patients returned fewer than 50% of their weekly measures.
Overall, “for PWS, weight and BMI seem to be feasible to measure remotely as a text message-based study. This method of data collection could be very useful for additional studies in the PWS population,” the researchers wrote.
These findings can inform future clinical trials of therapies for hyperphagia and obesity, they added, and provide data on how well they are performing in the real-world.
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