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The Kyleena® Satisfaction Study (KYSS)

KYSS study design1

This prospective, noninterventional, multinational, single-arm cohort study took place in Belgium, Canada, Germany, Mexico, Norway, Sweden, Spain, and the United States (US). All participants were women with different or no previously used contraceptive methods (including women without previous contraception forming one of the subgroups) who had already decided to use Kyleena. In the US, the study was conducted at 12 sites in 100 women. In Belgium, Canada, Mexico, Norway, Sweden, and Spain, the sample size was N = 100 in each country. Germany contained the largest sample size of N = 500. The primary endpoint was to evaluate overall satisfaction with Kyleena at the end of the observation period (12 months) per country. The secondary endpoints included satisfaction with Kyleena at the end of the observation period (12 months) stratified by previously used contraceptive method and motivation for choosing Kyleena, pain severity at Kyleena insertion, ease of Kyleena insertion (investigator assessed), and other measures.

KYSS participants were asked 2 questions pertaining to their contraception usage before having Kyleena placed2

The decision to use an LNG-IUS was made independently by the women after a discussion with their healthcare provider at participating study centers. These discussions were not prompted or scripted; the healthcare providers gave their routine counseling, after which the women could decide to use any contraception method. 

Why did you decide to stop your previous method of contraception?

Participants were asked to select from certain options, some of which include the following:

  • Afraid the contraceptive method might not be very effective
  • Problems with daily, weekly, or monthly contraceptive routine (intake, insertion, injection, application)
  • Dissatisfaction with current contraceptive method
  • Other, please specify

Why did you decide to use Kyleena for contraception? 

Participants were asked to select from certain options, some of which include the following:

  • High contraceptive reliability
  • No daily, weekly, or monthly contraceptive routine (intake, insertion, injection, application)
  • Acts mainly locally
  • Low hormone dose
  • Estrogen-free contraception
  • Small size
  • Other, please specify

Understanding the effects of these variables on satisfaction rates may help healthcare providers assist in the counseling and method selection process.

Safety results from the clinical trials3


System Organ ClassAdverse ReactionIncidence(%)
Reproductive System and Breast DisordersVulvovaginitis24.3
Ovarian cysta22.2
Dysmenorrhea/uterine spasm8.0/2.4
Increased bleedingb7.9
Breast pain/discomfort7.1/3.5
Gential discharge4.5
Device expulsion (complete and partial)3.5
Upper genital tract infection1.5
Gastrointestinal DisordersAbdominal pain/pelvic pain13.3/8.2

In the clinical trials, serious adverse reactions occurring in more than a single subject included: ectopic pregnancy/ruptured ectopic pregnancy (10 subjects); pelvic inflammatory disease (6 subjects); missed abortion/incomplete spontaneous abortion/spontaneous abortion (4 subjects); ovarian cyst (3 subjects); abdominal pain (4 subjects); depression/affective disorder (4 subjects); and uterine perforation/embedded device (myometrial perforation) (3 subjects).

aOvarian cysts were reported as adverse events if they were abnormal, non-functional cysts and/or had a diameter >3 cm on ultrasound examination.

bNot all bleeding alterations were captured as adverse reactions.

Safety results and limitations from the KYSS study

Treatment-emergent adverse events (TEAEs) reported in ≥1% of women who received Kyleena in KYSS (N=1129)2

Reproductive system and breast disorders 89 (7.9%)
Vaginal hemorrhage 21 (1.9%)
Dysmenorrhea 11 (1.0%)
Menorrhagia 11 (1.0%)
Gastrointestinal disorders 29 (2.6%)
Abdominal pain (lower) 16 (1.4%)
Psychiatric disorders 13 (1.2%)
Skin and subcutaneous tissue disorders 13 (1.2%)

Women who were using Kyleena most frequently reported TEAEs related to the reproductive system and breast disorders (89 patients, 7.9%), gastrointestinal disorders (29 patients, 2.6%), psychiatric disorders (13 patients,1.2%), and skin and subcutaneous tissue disorders (13 patients, 1.2%). The most frequently reported TEAEs in women using Kyleena were vaginal hemorrhage (21 patients, 1.9%) and lower abdominal pain (16 patients, 1.4%). A total of 69 patients (6.1%) discontinued Kyleena due to TEAEs, 4 of these patients (0.4%) due to treatment-emergent serious adverse events.

Potential study limitations2

  • Given the noninterventional study design and limitations inherent to observational studies, findings generated from this study are subject to biases, such as selection bias, limitations to availability of historical medical data, and differences in treatment or reporting owing to local guidelines
  • The study population was enrolled in selected countries and sites that might not be comparable to the nonparticipating population. This might also be a limiting factor in generalizing the results
  • Investigators were chosen based on feasibility criteria, which might have resulted in decreased generalizability of the study results
  • Selection bias could not be excluded completely because potential study participants were predominantly selected among those who wanted to change their previously used contraceptive method because of unsatisfactory experiences
  • Since this kind of bias could not be ruled out, an additional group of women without previous contraception (new starters) were included. Results of this subgroup enabled putting the satisfaction results into the right perspective