Official complaints about healthcare are likely to be the "tip of an iceberg," with many more people feeling they have legitimate cause to complain, but not doing so, particularly those with bad experiences of services, suggests research published in BMJ Open.
Not having the energy, thinking it will make no difference, and not knowing where to turn were some of the principal deterrents, the study showed.
The authors base their findings on a random sample of 1500 adults living in Stockholm, Sweden in 2008, who were asked about their experiences of healthcare (positive or negative).
They were also asked whether they had ever filed an official complaint about a staff encounter as a patient or relative, and whether they had ever not done so, despite having legitimate cause.
In all, 992 people replied, giving a response rate of 62%. Good experiences outnumbered bad ones by almost two to one (just over 60% compared with 34%); 5.5% of respondents had had no experience of healthcare.
Among the 867 respondents with complete/relevant data, those with good experiences complained less. Just 1.5% lodged a formal complaint, compared with just under one in 20 (4.8%) of those with poor experiences.
But none the less, almost 8% of those with a good experience said they had reason to complain, but had not done so. And this figure rose to almost four out of 10 (37%) among those with poor experiences.
Across the whole sample, this equates to an official complaint rate of just under 3% (23 people), with almost one in five people (18.5%; 159) feeling they had grounds for complaint, but not acting on them, say the authors.
They found a strong association between the type of experience and trust in healthcare, with those with poor experiences saying they had little trust, and those with good experiences saying they had a great deal of trust in healthcare.
Among those who said they had reason to complain but had not done so, one in three had little trust in healthcare. Nine out of 10 of those who had not reason to lodge a complaint, said they had a high level of trust in healthcare.
The authors point out that trust in healthcare is key to getting patients to comply with treatment and, ultimately, to maintaining patient safety.
"I did not have the strength;" "I did not know where to turn;" and "it makes no difference anyway" were the most common responses for not making a complaint, despite feeling there were grounds to do so.
Other stated reasons included finding the procedure too difficult and fearing reprisals, something which the authors describe as "alarming."
They point out that while only a small proportion of the large number of annual healthcare visits in Stockholm attract complaints, the number is steadily rising.
"[Our] study indicates that healthcare complaints filed reveal only the tip of an iceberg. Complaints seem to be considerably under reported, especially among those with a negative general experience of healthcare" they conclude.
This has implications for the development of effective services and for the future prevention of mistakes, they suggest.