International Active Surveillance Study of Women Taking Oral Contraceptives (INAS-OC)

International Active Surveillance Study of Women Taking Oral Contraceptives (INAS OC)

The study compares the short- and long-term risks of a 24-day regimen of a drospirenone-containing oral contraceptive with the risks of established oral contraceptives in a study population that is representative for the actual users of the individual preparations.

Study Overview

• Status: Completed
• Conditions: Contraception

Detailed Description

Drospirenone is a novel progestogen with antiandrogenic and antimineralocorticoid properties. A large active post-marketing surveillance study has demonstrated that a 21-day regimen of 3mg drospirenone and 30mcg ethinylestradiol can be used safely for oral contraception. This study investigates the risks of short and long-term use of a 24-day regimen of drospirenone/ethinylestradiol in comparison to established OCs in a study population that is representative of the actual users of the individual preparations.

INAS-OC is a prospective, controlled, non-interventional cohort study with two study arms: OCs containing drospirenone and OCs containing any other progestogen. The study was started in the USA in April 2005 and was extended to several European countries in September 2008 based on the launch status of the 24-day regimen. New users of an OC (starters, switchers without a pill intake break and recurrent users with a pill intake break [same or different OC]) are accrued by a network of prescribing physicians. Baseline and follow-up information are collected via a self-administered questionnaire. Data analysis will be based on life-table methods comparing the cohorts. All analyses will make allowance for confounding, using methods that will include multivariate techniques such as Cox regression.

• Study Type: Observational
• Enrollment (Actual): 85109

Contacts and Locations

Study Locations

• Germany
  • Berlin, Germany, 10115
    • Center for Epidemiology and Health Research

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

• Sampling Method: Non-Probability Sample

Study Population

Women using oral contraceptives

Description

Inclusion Criteria:

• First-ever OC users ("starters")
• Women switching OC use without a pill intake break ("switchers")
• Recurrent users with a pill intake break ("recurrent users")
• Women willing to participate in the active surveillance

Exclusion Criteria:

• Women who do not agree to participate
• Long-term users

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
1; Users of OCs containing DRSP
2; Users of OCs containing other progestins

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Venous Thromboembolism (VTE); Hazard Ratio for DRSP-24 Day vs. Non-DRSP OCs	Venous thromboembolism (VTE) hazard ratio for oral contraceptives containing both drospirenone (DRSP) and ethinylestradiol (EE) in a 24-day regimen or any oral contraceptive without DRSP.	Within 60 months
Arterial Thromboembolism (ATE), Hazard Ratio for DRSP-24 Day vs. Non-DRSP OCs	Arterial thromboembolism (ATE) in women using oral contraceptives containing both drospirenone (DRSP) and ethinylestradiol (EE) in a 24-day regimen or any oral contraceptive without DRSP. Cox regression analysis was not carried out. In accordance to the analysis plan, hazard ratios were only to be calculated if a minimum of 5 confirmed events were available in each of the comparison groups.	Within 60 months

Collaborators and Investigators

• Sponsor: Center for Epidemiology and Health Research, Germany
• Collaborators: Bayer
• Investigators: Principal Investigator: Juergen C Dinger, MD, PhD, Center for Epidemiology and Health Research, Berlin, Germany

Publications and helpful links

General Publications

• Dinger J, Bardenheuer K, Heinemann K. Cardiovascular and general safety of a 24-day regimen of drospirenone-containing combined oral contraceptives: final results from the International Active Surveillance Study of Women Taking Oral Contraceptives. Contraception. 2014 Apr;89(4):253-63. doi: 10.1016/j.contraception.2014.01.023. Epub 2014 Feb 4.
• Dinger J, Do Minh T, Buttmann N, Bardenheuer K. Effectiveness of oral contraceptive pills in a large U.S. cohort comparing progestogen and regimen. Obstet Gynecol. 2011 Jan;117(1):33-40. doi: 10.1097/AOG.0b013e31820095a2.

Study record dates

Study Major Dates

• Study Start: August 1, 2005
• Primary Completion (Actual): January 1, 2013
• Study Completion (Actual): March 1, 2013

Study Registration Dates

• First Submitted: June 8, 2006
• First Submitted That Met QC Criteria: June 8, 2006
• First Posted (Estimate): June 9, 2006

Study Record Updates

• Last Update Posted (Actual): August 7, 2019
• Last Update Submitted That Met QC Criteria: August 6, 2019
• Last Verified: August 1, 2019

More Information

Terms related to this study

• Keywords: Safety; Drospirenone; INAS
• Other Study ID Numbers: ZEG 2005-2