The study will be conducted in various European hospitals over a total duration of 10 years. The participation of Swiss, German and Italian centers is planned. Hospitals in other European countries could also take part in the study. At least 1000 patients will take part in the study. We expect that around 300 of these patients at the University Hospital Zurich can be included in the study. Each study participant must expect two visits to the outpatient clinic of the Department of Endocrinology at the University Hospital Zurich. If the examination findings indicate the presence of primary hyperaldosteronism or if a particularly low potassium level is found, one to a maximum of two additional visits should be expected. All the examinations mentioned below correspond to the usual clinical routine. You will only be asked to give a little more blood and urine than would otherwise be necessary. This project will be carried out in accordance with Swiss law. The responsible ethics committee has examined and approved this project.
Aim of the study
Primary hyperaldosteronism is a disease of the adrenal glands that can be cured in principle. The adrenal glands are glands that lie on either side of the kidneys and produce hormones that regulate blood pressure, among other things. In primary hyperaldosteronism, the hormone aldosterone is produced in excess, which causes high blood pressure. In the long term, high blood pressure causes the development of heart disease and strokes, making it one of the most common causes of death worldwide. It is assumed that primary hyperaldosteronism is responsible for high blood pressure in 8-12% of all cases. Unfortunately, the disease is often not recognized or only recognized late. This study therefore aims to improve the detection of primary hyperaldosteronism in the long term. To this end, we would like to find out how frequently primary hyperaldosteronism occurs in patients with low blood potassium levels, a characteristic side effect of the disease. The potassium value can be used to help decide when it makes sense to search for the disease. The results of the study could be used to formulate precise recommendations for GPs and hospital doctors on how to look for the disease depending on the potassium level. Consequential complications and healthcare costs would be reduced by early detection and treatment of primary hyperaldosteronism.
Who can take part?
All adults who have been found to have low blood potassium levels during an outpatient examination at the University Hospital Zurich (USZ) are eligible. Patients with a serious illness which, in the opinion of their doctor, makes participation impossible, women during a known pregnancy or patients with impaired mental capacity and judgment are excluded from participation in this study.
Procedure
1st visit:
All participants are first asked about their state of health and medical history. Information on medication intake and the presence of cardiovascular or other concomitant diseases is particularly important for the study. In addition, participants receive a physical examination, a cardiac waveform examination (ECG) and a 24-hour ambulatory blood pressure measurement. In addition, urine and blood samples are taken from all participants (maximum 50 ml blood, 1 urine tube, 24-hour urine collection). The blood sample must be taken on an empty stomach. This means that you must not eat the night before the blood sample is taken (for a period of at least 8 hours); drinking water is permitted during this time. As the consumption of liquorice can influence some of the measured values, you should avoid eating liquorice in the week before the performance. For some patients, a temporary change in blood pressure medication will be necessary in preparation for the examination. This procedure corresponds to standard clinical practice. The appointment will take about 1.5 hours of your time.
Some examination procedures are described in more detail below:
- ECG:
An electrocardiogram (ECG) records the heart currents and indicates structural heart damage.
- 24-hour outpatient blood pressure measurement:
The long-term blood pressure monitors comply with normal standards. A blood pressure cuff is placed on the upper arm and connected to a small recording device worn on the body. The long-term blood pressure monitor is put on by us in the morning and taken back by us in the morning of the following day. Blood pressure measurements are taken every 15 minutes over 24 hours during the day and every half hour at night. Normally, patients tolerate wearing the device and the frequent blood pressure measurements well. You can of course remove the blood pressure monitor for personal hygiene (e.g. showering). You will receive instructions on how to put the device on and take it off independently for these purposes. In addition to the measurements, you should also keep a diary so that we can track the daily activity with which the measured blood pressure correlates.
- 24-hour urine collection:
You will be given one or more urine collection containers for the urine tests and you will receive detailed instructions on how to collect your urine over 24 hours. A prompt return of the urine-filled collection containers to the outpatient clinic within half a day after the end of urine collection should be ensured.
2nd visit:
If the blood tests provide evidence of the presence of primary hyperaldosteronism, we will plan a further laboratory test for the relevant participants, which is necessary to definitively confirm or rule out the disease. A maximum of 15 ml of blood is taken. You do not have to appear sober for this. This means that you can eat and drink before the examination. However, as the consumption of licorice can influence some of the measured values, you should avoid eating licorice in the week before the performance. For some patients, a temporary change in blood pressure medication will be necessary in preparation for the examination. This procedure corresponds to standard clinical practice. This appointment will take approximately 4.5 hours of your time.
3rd visit:
Participants whose potassium levels are below a certain limit are asked to take potassium tablets for a week according to an exact prescription to correct the potassium level in their blood. The administration of potassium when blood potassium levels are low corresponds to routine treatment. After one week, we collect urine and blood again (maximum 50 ml blood, 1 urine tube, 24-hour urine collection). You do not have to appear sober for this. This means that you can eat and drink before the examination. However, as the consumption of licorice can influence some of the measured values, you should avoid eating licorice in the week before the performance. We also repeat the 24-hour blood pressure measurement. The appointment will take about 15 minutes of your time.
4th visit:
All study participants are invited to a final visit after one year. This visit includes a new health questionnaire, a physical examination and the collection of urine and blood samples (maximum 50 ml blood, 1 urine tube, 24-hour urine collection). The blood sample must be taken on an empty stomach. This means that you must not eat the night before the blood sample is taken (for a period of at least 8 hours); drinking water is permitted during this time. As the consumption of liquorice can influence some of the measured values, you should avoid eating liquorice in the week before the performance. The appointment will take about 1 hour of your time.
Your family doctor will be informed about your participation and the test results. If you do not wish to do this, please speak to your investigator/project management.
Compensation
They do not receive an expense allowance. Examinations that are part of the routine clinical procedure for low potassium levels anyway (ECG, 24-hour blood pressure measurement, routine laboratory tests) are carried out as part of outpatient examinations.
Original study name
Incidence of Primary Aldosteronism in Patients with Hypokalemia (IPAHK+)
BASEC number
2019-00832
Sponsors
The project is fully funded by the National Center of Competence in Research (NCCR), which is managed by the Swiss National Science Foundation (SNSF) and supported by the Swiss government.