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Adults who used thiazide diuretics for hypertension were more likely than were those who used nonthiazide agents to develop hyponatremia within 2 years of starting treatment, a new study of more than 180,000 people has found.
Although thiazide diuretics generally are well-tolerated in the routine treatment of uncomplicated hypertension, severe adverse effects are possible, and their frequency has not been examined, according to Niklas Worm Andersson, MD, of Statens Serum Institut, in Copenhagen, Denmark, and his colleagues.
“Thiazide diuretics are commonly used drugs for the treatment of uncomplicated hypertension, and hyponatremia is a known potential side effect to thiazide treatment, but the frequency of this adverse event is inconsistently reported across drug labels,” Dr. Andersson told this news organization.
Product labels for thiazide diuretics list hyponatremia as a potential adverse event that can occur rarely (defined as a range from less than 1 in 10,000 to less than 1 in 100 individuals), but the extent of the burden is unclear given the wide range of symptoms of the condition, the researchers write.
In a study published in Annals of Internal Medicine, Dr. Andersson and his colleagues reviewed data from population-based registries in Denmark of adults aged 40 years or older with uncomplicated hypertension, no recent prescriptions for antihypertensives, and no previous history of hyponatremia. They emulated two target trials. One trial compared the incidence of hyponatremia in new users of bendroflumethiazide (BFZ) vs a calcium-channel blocker (CCB). The other emulation compared the incidence of hyponatremia in new users of hydrochlorothiazide (HCTZ) plus a renin-angiotensin system (RAS) inhibitor vs a RAS inhibitor without HCTZ.
The primary outcome was hyponatremia, defined as blood sodium < 130 mmol/L, within 2 years of starting treatment.
The 2-year incidence of hyponatremia for the two thiazide diuretics was 3.83% for BFZ and 3.51% for HCTZ-RAS inhibitor. The risk difference in the incidence of hyponatremia was 1.35% for BFZ vs CCB and 1.38% for HCTZ-RAS inhibitor vs RAS inhibitor, the researchers reported.
The study population included 37,786 new users of BFZ who were compared with 44,963 new users of CCBs as well as 11,943 new users of HCTZ-RAS inhibitors who were compared with 85,784 new users of RAS inhibitors only.
Overall, older age and a greater number of comorbidities increased the cumulative hyponatremia in new users of thiazide-based hypertensives. The risk differences among individuals aged 80 years or older were 4.80% in the BFZ vs CCB study and 5.52% in the HCTZ-RAS inhibitor vs RAS inhibitor study. Among participants with three or more comorbidities, the risk differences in the two studies were 5.24% and 2.91%, respectively, Dr. Andersson’s group found.
The findings were limited by several factors, mainly the potential for confounding on the basis of the assumption that filled prescriptions equaled drug use, the researchers noted. Other limitations included the focus on new users and a Danish population only, which might limit generalizability, and a lack of data on blood pressure measures.
However, the results suggest a greater risk for hyponatremia with thiazide diuretics than what the drug labels indicate, especially early in treatment, the researchers concluded.
Data Reinforce Need for Vigilance in the Clinic
“Our findings highlight the continued need for clinical awareness and monitoring of this adverse drug reaction; particularly during the first months of treatment, in persons who are older or who have comorbidities,” Dr. Andersson told this news organization. “Further mapping of potential subpopulations at risk in terms of specific comorbidities is important to improve the prevention of this adverse event.”
“The thiazide diuretics have been recommended as first-line therapy for hypertension, and it was important to evaluate the potential development of hyponatremia, especially in the older patients given the potentially serious health effects caused by hyponatremia,” said Noel Deep, MD, a general internist in private practice in Antigo, Wisconsin. Dr. Deep, who was not involved in the study, also serves as chief medical officer and a staff physician at Aspirus Langlade Hospital in Antigo.
The current study findings were not surprising, Dr. Deep added. “I have seen this occur in my patients, especially in the older female patients,” he said. “The results reinforce my practice of monitoring the electrolytes and renal function in 1-2 weeks after starting a thiazide diuretic, and then at regular intervals.”
In practice, clinicians should be aware of the potential development of hyponatremia and monitor and address the electrolyte abnormalities, Dr. Deep said. “While thiazide and thiazide-like diuretics are an important component of our treatment options for patients with hypertension and other conditions, we should also ensure that we are cognizant of and address the potential side effects or electrolyte imbalances caused by the medications.”
The study was funded by the Independent Research Fund Denmark, Helsefonden, Dagmar Marshalls Fond, Gangstedfonden, A.P. Møller and Chastine Mc-Kinney Møller Foundation, Brødrene Hartmanns Fond, and Snedkermester Sophus Jacobsen og hustru Astrid Jacobsens Fond.
The researchers had no financial conflicts to disclose. Dr. Deep had no financial conflicts to disclose.
A version of this article first appeared on Medscape.com.
Adults who used thiazide diuretics for hypertension were more likely than were those who used nonthiazide agents to develop hyponatremia within 2 years of starting treatment, a new study of more than 180,000 people has found.
Although thiazide diuretics generally are well-tolerated in the routine treatment of uncomplicated hypertension, severe adverse effects are possible, and their frequency has not been examined, according to Niklas Worm Andersson, MD, of Statens Serum Institut, in Copenhagen, Denmark, and his colleagues.
“Thiazide diuretics are commonly used drugs for the treatment of uncomplicated hypertension, and hyponatremia is a known potential side effect to thiazide treatment, but the frequency of this adverse event is inconsistently reported across drug labels,” Dr. Andersson told this news organization.
Product labels for thiazide diuretics list hyponatremia as a potential adverse event that can occur rarely (defined as a range from less than 1 in 10,000 to less than 1 in 100 individuals), but the extent of the burden is unclear given the wide range of symptoms of the condition, the researchers write.
In a study published in Annals of Internal Medicine, Dr. Andersson and his colleagues reviewed data from population-based registries in Denmark of adults aged 40 years or older with uncomplicated hypertension, no recent prescriptions for antihypertensives, and no previous history of hyponatremia. They emulated two target trials. One trial compared the incidence of hyponatremia in new users of bendroflumethiazide (BFZ) vs a calcium-channel blocker (CCB). The other emulation compared the incidence of hyponatremia in new users of hydrochlorothiazide (HCTZ) plus a renin-angiotensin system (RAS) inhibitor vs a RAS inhibitor without HCTZ.
The primary outcome was hyponatremia, defined as blood sodium < 130 mmol/L, within 2 years of starting treatment.
The 2-year incidence of hyponatremia for the two thiazide diuretics was 3.83% for BFZ and 3.51% for HCTZ-RAS inhibitor. The risk difference in the incidence of hyponatremia was 1.35% for BFZ vs CCB and 1.38% for HCTZ-RAS inhibitor vs RAS inhibitor, the researchers reported.
The study population included 37,786 new users of BFZ who were compared with 44,963 new users of CCBs as well as 11,943 new users of HCTZ-RAS inhibitors who were compared with 85,784 new users of RAS inhibitors only.
Overall, older age and a greater number of comorbidities increased the cumulative hyponatremia in new users of thiazide-based hypertensives. The risk differences among individuals aged 80 years or older were 4.80% in the BFZ vs CCB study and 5.52% in the HCTZ-RAS inhibitor vs RAS inhibitor study. Among participants with three or more comorbidities, the risk differences in the two studies were 5.24% and 2.91%, respectively, Dr. Andersson’s group found.
The findings were limited by several factors, mainly the potential for confounding on the basis of the assumption that filled prescriptions equaled drug use, the researchers noted. Other limitations included the focus on new users and a Danish population only, which might limit generalizability, and a lack of data on blood pressure measures.
However, the results suggest a greater risk for hyponatremia with thiazide diuretics than what the drug labels indicate, especially early in treatment, the researchers concluded.
Data Reinforce Need for Vigilance in the Clinic
“Our findings highlight the continued need for clinical awareness and monitoring of this adverse drug reaction; particularly during the first months of treatment, in persons who are older or who have comorbidities,” Dr. Andersson told this news organization. “Further mapping of potential subpopulations at risk in terms of specific comorbidities is important to improve the prevention of this adverse event.”
“The thiazide diuretics have been recommended as first-line therapy for hypertension, and it was important to evaluate the potential development of hyponatremia, especially in the older patients given the potentially serious health effects caused by hyponatremia,” said Noel Deep, MD, a general internist in private practice in Antigo, Wisconsin. Dr. Deep, who was not involved in the study, also serves as chief medical officer and a staff physician at Aspirus Langlade Hospital in Antigo.
The current study findings were not surprising, Dr. Deep added. “I have seen this occur in my patients, especially in the older female patients,” he said. “The results reinforce my practice of monitoring the electrolytes and renal function in 1-2 weeks after starting a thiazide diuretic, and then at regular intervals.”
In practice, clinicians should be aware of the potential development of hyponatremia and monitor and address the electrolyte abnormalities, Dr. Deep said. “While thiazide and thiazide-like diuretics are an important component of our treatment options for patients with hypertension and other conditions, we should also ensure that we are cognizant of and address the potential side effects or electrolyte imbalances caused by the medications.”
The study was funded by the Independent Research Fund Denmark, Helsefonden, Dagmar Marshalls Fond, Gangstedfonden, A.P. Møller and Chastine Mc-Kinney Møller Foundation, Brødrene Hartmanns Fond, and Snedkermester Sophus Jacobsen og hustru Astrid Jacobsens Fond.
The researchers had no financial conflicts to disclose. Dr. Deep had no financial conflicts to disclose.
A version of this article first appeared on Medscape.com.
Adults who used thiazide diuretics for hypertension were more likely than were those who used nonthiazide agents to develop hyponatremia within 2 years of starting treatment, a new study of more than 180,000 people has found.
Although thiazide diuretics generally are well-tolerated in the routine treatment of uncomplicated hypertension, severe adverse effects are possible, and their frequency has not been examined, according to Niklas Worm Andersson, MD, of Statens Serum Institut, in Copenhagen, Denmark, and his colleagues.
“Thiazide diuretics are commonly used drugs for the treatment of uncomplicated hypertension, and hyponatremia is a known potential side effect to thiazide treatment, but the frequency of this adverse event is inconsistently reported across drug labels,” Dr. Andersson told this news organization.
Product labels for thiazide diuretics list hyponatremia as a potential adverse event that can occur rarely (defined as a range from less than 1 in 10,000 to less than 1 in 100 individuals), but the extent of the burden is unclear given the wide range of symptoms of the condition, the researchers write.
In a study published in Annals of Internal Medicine, Dr. Andersson and his colleagues reviewed data from population-based registries in Denmark of adults aged 40 years or older with uncomplicated hypertension, no recent prescriptions for antihypertensives, and no previous history of hyponatremia. They emulated two target trials. One trial compared the incidence of hyponatremia in new users of bendroflumethiazide (BFZ) vs a calcium-channel blocker (CCB). The other emulation compared the incidence of hyponatremia in new users of hydrochlorothiazide (HCTZ) plus a renin-angiotensin system (RAS) inhibitor vs a RAS inhibitor without HCTZ.
The primary outcome was hyponatremia, defined as blood sodium < 130 mmol/L, within 2 years of starting treatment.
The 2-year incidence of hyponatremia for the two thiazide diuretics was 3.83% for BFZ and 3.51% for HCTZ-RAS inhibitor. The risk difference in the incidence of hyponatremia was 1.35% for BFZ vs CCB and 1.38% for HCTZ-RAS inhibitor vs RAS inhibitor, the researchers reported.
The study population included 37,786 new users of BFZ who were compared with 44,963 new users of CCBs as well as 11,943 new users of HCTZ-RAS inhibitors who were compared with 85,784 new users of RAS inhibitors only.
Overall, older age and a greater number of comorbidities increased the cumulative hyponatremia in new users of thiazide-based hypertensives. The risk differences among individuals aged 80 years or older were 4.80% in the BFZ vs CCB study and 5.52% in the HCTZ-RAS inhibitor vs RAS inhibitor study. Among participants with three or more comorbidities, the risk differences in the two studies were 5.24% and 2.91%, respectively, Dr. Andersson’s group found.
The findings were limited by several factors, mainly the potential for confounding on the basis of the assumption that filled prescriptions equaled drug use, the researchers noted. Other limitations included the focus on new users and a Danish population only, which might limit generalizability, and a lack of data on blood pressure measures.
However, the results suggest a greater risk for hyponatremia with thiazide diuretics than what the drug labels indicate, especially early in treatment, the researchers concluded.
Data Reinforce Need for Vigilance in the Clinic
“Our findings highlight the continued need for clinical awareness and monitoring of this adverse drug reaction; particularly during the first months of treatment, in persons who are older or who have comorbidities,” Dr. Andersson told this news organization. “Further mapping of potential subpopulations at risk in terms of specific comorbidities is important to improve the prevention of this adverse event.”
“The thiazide diuretics have been recommended as first-line therapy for hypertension, and it was important to evaluate the potential development of hyponatremia, especially in the older patients given the potentially serious health effects caused by hyponatremia,” said Noel Deep, MD, a general internist in private practice in Antigo, Wisconsin. Dr. Deep, who was not involved in the study, also serves as chief medical officer and a staff physician at Aspirus Langlade Hospital in Antigo.
The current study findings were not surprising, Dr. Deep added. “I have seen this occur in my patients, especially in the older female patients,” he said. “The results reinforce my practice of monitoring the electrolytes and renal function in 1-2 weeks after starting a thiazide diuretic, and then at regular intervals.”
In practice, clinicians should be aware of the potential development of hyponatremia and monitor and address the electrolyte abnormalities, Dr. Deep said. “While thiazide and thiazide-like diuretics are an important component of our treatment options for patients with hypertension and other conditions, we should also ensure that we are cognizant of and address the potential side effects or electrolyte imbalances caused by the medications.”
The study was funded by the Independent Research Fund Denmark, Helsefonden, Dagmar Marshalls Fond, Gangstedfonden, A.P. Møller and Chastine Mc-Kinney Møller Foundation, Brødrene Hartmanns Fond, and Snedkermester Sophus Jacobsen og hustru Astrid Jacobsens Fond.
The researchers had no financial conflicts to disclose. Dr. Deep had no financial conflicts to disclose.
A version of this article first appeared on Medscape.com.
FROM ANNALS OF INTERNAL MEDICINE